


.^Illllllllll 



TESTING MILK 

AND ITS PRODUCTS 



FARRINQTON and WOLL 



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Dr. S. M. BABCOCK, 

INVENTOR OF THE BABCOCK MILK TEST. 



TESTING MILK 

ANB ITS PRODUCTS 



A MANUAL FOR DAIRY STUDENTS, CREAMERY- AND CHEESE 

FACTORY OPERATORS, FOOD CHEMISTS, AND 

DAIRY FARMERS 



E. H. FARRINGTON and F. W. WOLL 

Professor in Charge of Dairy School Asst. Prof, of AgrH Chemistry 

Of the University of Wisconsin 



•CQlitb ^Ilut^tration^ 



THIRTEENTH REVISED AND ENLARGED EDITION 



MADISON, WIS. 

Mendota Book Company 

1904 

ALL RIGHTS RESERVED 



THE LIBPA^v OF 

CONGRE9R. 
Onp Conr Receivcp 

lyiAY. 2 1904 

COPVWeHT ENTPV 

CCASsO '^t XXa N«. 
COPY B. 



Copyright, 1897, 1899, 1901 and 1904, 
By E. H. FARHINGTON and F. W. WOLL. 






CANTWELIi PRINTING COMPANY 
MADISON, WIS. 



PREFACE TO FIRST EDITION. 



The present volume is intended for the use of dairy students, 
factory operators, dairymen, food chemists, and others inter- 
ested in the testing or analysis of milk and its products. The 
subject has been largely treated in a popular manner; accuracy 
and clearness of statement, and systematic arrangement of the 
subject matter have, however, been constantly kept in mind. 
The aim has been to make the presentation intelligible to 
students with no further training than a common-school educa- 
tion, but their work will naturally be greatly lightened by the 
aid of an able teacher. 

Complete directions for making tests of milk and other dairy 
products are given; difficulties which the beginner may meet 
with are considered in detail, and suggestions offered for avoid- 
ing them. It is expected that a factory operator or practical 
dairyman, by exercising common sense and ordinary care, can 
obtain sufficient knowledge of the subject through a study of 
the various chapters of this book to make tests of milk, cream, 
etc., even if he has had no previous experience in this line. 

For the benefit of advanced dairy students who are some- 
what familiar with chemistry and chemical operations. Chapter 
XIV has been added giving detailed instructions for the com- 
plete chemical analysis of milk and other dairy products. The 
detection of preservatives and of artificial butter or filled cheese 
has also been treated in this connectton. 

As the subject of milk testing is intimately connected with 
the payment for the milk delivered at butter- and cheese fac- 
tories, and with factory dividends, a chapter has been devoted 
to a discussion of the various systems of factory book-keeping, 
and tables greatly facilitating the work of the factory secretary 
or bookkeeper have been prepared and are included in the 
Appendix. 



iv Testing Milk and Its Products. 

Acknowledgment is due to the following parties for the use 
of electrotypes, viz.: Creamery Pkg. Mfg. Co., Chicago, 111.; 
Vermont Farm Machine Co., Bellows Falls, Vt.; Elgin Mfg. 
Co., Elgin, 111.; D. H. Burrell & Co., Little Falls, N. Y.; De 
Laval Separator Co., New York City; Henry Tromner, Phila- 
delphia, Pa.; Springer Torsion Balance Co., New York City; 
J. H. Monrad, Winnetka, 111.; Borden & Selleck Co., Chicago, 
111.; Dairymen's Supply Co., Philadelphia, Pa.; Bausch & 
Lomb Opt. Co., Rochester, N. Y.; John W. Decker, Columbus, 
Ohio; C. L. Fitch, Forth Atkinson, Wis., and the agricultural 
experiment stations at New Haven, Conn., and Madison, Wis. 

Madison, Wis., October 1, 1897. 



PREFACE TO THIRTEENTH EDITION. 



The first three editions of this book were sold in about a 
year and the twelfth edition was exhausted six years later. 
Every year that passes brings some valuable contributions to 
our knowledge of the subjects treated in the book and a fre- 
quent revision of it is therefore desirable. 

The present edition contains all the methods and descrip- 
tions that have stood the test of actual use during the past few 
years; the new information which has appeared since the 
last revision of the book, has been carefully sifted, and what 
was deemed of sufficient importance has been incorporated in 
such detail as the scope of the book permitted; many changes 
and additions suggested by the experience of the authors have 
also been introduced. In brief, the book has been subjected to 
a renewed, critical examination and revision. The general 
adoption of it as a text book in American Dairy Schools, as well 
as the favorable reception which it has been accorded by users 
of Babcock testers, and the dairy public in general, is naturally 
a source of gratification to the authors. 

Madison, Wis., March 25, 1904. 



TABLE OF CONTENTS. 



Page. 

Introduction 1 

Chap. I. Composition of milk and its products . . 11 

Composition of milk: Water. Fat. Casein and albu- 
men. Milk sugar (lactose). Ash. Other components. 
Colostrum milk. Composition of milk products. 
Chap. II. Sampling milk 23 

Sweet milk. Partially churned milk. Sour milk. 
Frozen milk. 
Chap. III. The Babcock test — Milk 28 

A. Directions for making the test: 

Sampling. Adding acid. Mixing milk and acid. 
Whirling bottles. Adding water. Measuring the fat. 
Lutley dividers. 

B. Discussion of the details of the test : 

1. Glassware. Test bottles. Pipettes. "Fool pipettes." 
Acid measures. The Swedish acid bottle. Calibration of 
glassware. Calibration with mercury. Calibration with 
water. The Trowbridge method of calibration. 

2. Centrifugal machines. Speed required for the com- 
plete separation of the fat. Ascertaining the necessary 
speed of testers. Hand testers. Power testers. 

3. Sulfuric acid. Testing the strength of the acid. The 
Swedish acid tester. The color of the fat column an index 
to the strength of the acid used. Influence of temperature 
on the separation of fat. 

4. Water to be used in the Babcock test. Reservoir for 
water. 

5. Modifications of the Babcock test. The Russian milk 
test. Bartlett's modification. Siegfeld's modification. 
Bausch and Lomb centrifuge. 

Chap. IV. The Babcock test — Cream 74 

Errors of measuring the cream. Weighing cream. 
Cream-test bottles. The bulb-necked cream bottle. The 
Winton cream bottle. Cream-weighing scales. Measur- 
ing cream for testing. Use of milk test bottle. Use of 
5 cc pipette. Proper readings of cream tests. 



vi Testing Milk and Its Products. 

Page. 
Chap. V. The B abcock test — other milk pro- 
ducts 85 

Skim milk, butter milk and whey. The double-necked 
test bottle. The Wagner test bottle. The double-sized 
skim milk bottle. Cheese. Condensed milk. 
Chap VI. The lactometer and its application . . 93 

The Quevenne lactometer. Influence of temperature. 
N. Y. Board of Health lactometer. Reading the lacto- 
meter. Time of taking lactometer readings. Influence of 
bi-chromate on lactometer reading. Calculation of milk 
solids. Adulteration of milk. Legal standards. The 
specific gravity of the milk solids. Calculation of extent 
of adulteration: Skimming. Watering. Watering and 
skimming. 
Chap VII. Testing the acidity of milk and cream 108 

Cause of acidity in milk. Methods of testing acidity. 
Manns' test. Devarda's acidimeter. The alkaline- tablet 
test. Determination of acidity in sour cream. Spillman's 
cylinder. Rapid estimation of the acidity of apparently 
sweet milk and cream. Detecting boracic-acid preserva- 
tives in milk. ' ' Alkaline Tabs. ' ' 
Chap. VIII. Testing the purity of milk 125 

The Wisconsin curd test. The fermentation test. The 
Monrad rennet test. The Marschall rennet test. 
Chap. IX. Testing milk on the farm 131 

Variations in milk of single cows. Number of tests re- 
quired during a period of lactation in testing cows. When 
to test a cow. Gurler's method. Sampling milk of single 
cows. Variations in herd milk. Influence of heavy grain 
feeding on the quality of milk. Influence of pasture on 
the quality of milk. Method of improving the quality of 
milk. 
Chap. X. Composite samples of milk 148 

Methods of taking composite samples. Use of tin 
dipper. Drip sample. Scovell sampling tube. The 
equity milk sampler. One-third sample pipette. Pre- 
servatives for composite samples. Care of composite 
samples. Fallacy of averaging percentages. A patron's 
dilemma. 



Table of Contents, vii 

Pagb. 
Chap. XI. Cream testing at creameries ..... 165 

The space system. The oil-test churn. The Babcock 
test for cream. Sampling and weighing. 

Chap. XII. Ca lculation of butter and cheese yields 176 

A. Calculation of yield of butter: Butter fat test and 
yield of butter. Variations in composition of butter. 
Overrun of churn over test. Factors influencing the 
overrun. Calculation of overrun. Conversion factor for 
butter fat. Butter yield from milk of different richness. 
Use of butter chart. Use of overrun table. 

B. Calculation of yield of cheese: From fat. From 
solids not fat and fat. From casein and fat. 

Chap. XIII. Calculating dividends 190 

A. Calculating dividends at creameries: Proprietary 
creameries. Co-operative creameries. Illustrations of 
calculations of dividends. Paying for butter delivered. 
Milk and cream dividends. Relative-value tables. 

B. Calculating dividends at cheese factories: Proprie- 
tary factories. Co-operative factories. 

Chap. XIV. Chemical analysis of milk and its pro- 
ducts 204 

Milk. Cream. Skim milk, butter milk, whey. Con- 
densed nailk. Butter. A practical method of estimat- 
ing salt in butter. Detection of artificial butter. Reich- 
ert-Wollny method (Volatile acids). Tests for the detec- 
tion of oleomargarine and renovated butter. The boiling 
test. The Waterhouse test. Cheese. Detection of oleo- 
margarine cheese ("Filled" cheese). 

Tests for adulteration Of milk and cream. Detection 
of pasteurized milk or cream. Boiled milk. Detection 
of preservatives in dairy products. Boracic acid. Bi-car- 
bonate of soda. Fluorids. Salicylic acid. Formalde- 
hyde. Government food standards. 

Appendix 233 

Table I. Composition of milk and its products. 
Table II. State and city standards for dairy products. 
Table III. Quevenne lactometer degrees correspond- 
ing to the scale of the N. Y. Board of Health lactometers. 



viii Testing Milk and Its Products. 

Page. 

Table IV. Value of — ^~ • for specific gravities from 
1.019 to 1.0369. 

Table V. Correction table for specific gravity of milk. 

Table VI. Per cent, of solids not fat, corresponding to 
to 6 per cent, of fat and lactometer readings of 26 to 36. 

Directions for the use of tables VII, VIII, IX and XI. 

Table VII. Pounds of fat in I to 10,000 pounds of milk 
testing 3 to 5.35 per cent. 

Table VIII. Pounds of fat in 1 to 1,000 lbs, of cream 
testiug 12.0 to 50.0 per cent. fat. 

Table IX. Amount due for butter fat, in dollars and 
cents, at 12 to 25 cents per pound. 

Table X. Relative- value tables. 

Table XI. Butter chart, showing calculated yield of 
butter, in pounds, from 1 to 10,000 pounds of milk testing 
3.0 to 5.3 per cent, of fat. 

Table XII. Overrun table, showing pounds of butter 
from 100 pounds of milk. 

Table XIII. Yield of cheese, corresponding to 2.5 to 6 
per cent, of fat, with lactometer readings of 26 to 36. 

Table XIV. Comparisons of Fahrenheit and Centi- 
grade (Celcius) thermometer scales. 

Table XV. Comparison of metric and customary 
weights and measures. 

Suggestions regarding the organization of co-operative 
creameries and cheese factories. 

Constitution and by-laws for co-operative factory asso- 
ciations. 

Index 264 



Testing Milk and its Products* 



INTRODUCTION. 



The need of a rapid, accurate and inexpensive method 
of determining the amount of butter fat in milk and other 
dairy products became more and more apparent, in this 
country and abroad, with the progress of the dairy in- 
dustry, and especially with the growth of the factory 
system of butter- and cheese making during the last few 
decades. So long as each farmer made his own butter 
and sold it to private customers or at the village grocery, 
it was not a matter of much importance to others whether 
the milk produced by his cows was rich or poor. But 
as creameries and cheese factories multiplied, and farm- 
ers in the dairy sections of our country became to a 
large extent patrons of one or the other of these, a sys- 
tem of equitable payment for the milk or cream delivered 
became a vital question. 

I. The creameries in existcDce in this country up to 

within fifteen years were nearly all conducted on the 

cream- gathering plan: the different patrons creamed 

their milk by the gravity process, and the cream was 

hauled to the creamery, usually twice or three times a 

week, where it was then ripened and churned. The 

patrons were paid per inch of cream furnished; a creamery 

inch is a quantity of cream which fills a can twelve inches 
1 



2 Testing Milk and Its Products. 

in diameter, one inch high, or 113 cubic inches. This 
quantity of cream was supposed to make a pound of but- 
ter, but cream from different sources, or even from the 
same sources at different times, varies greatly in butter- 
producing capacity, as will be shown under the subject 
of cream testing (210 1). The system of paying for the 
number of creamery inches delivered could not therefore 
long give satisfaction. 

The proposition to take out a small portion, a pint or 
half a pint, of the cream furnished by each patron, and 
determine the amount of butter which these samples 
would make on being churned in so-called test churns, 
found but a very limited acceptance, on account of the 
labor involved and the difficulty of producing a first-class 
article from all the small batches of butter thus obtained. 

2. The introduction of the so-called oil test churn in 
creameries which followed the creamery- inch system, 
marked a decided step in advance, and it soon came into 
general use in gathered- cream factories (203). In this 
test, glass tubes of about f inch internal diameter and 
nine inches long, are filled with cream to a depth of five 
inches, and the cream is churned; the tubes are then placed 
in hot water, and the column of melted butter formed at 
the top is read off by means of a scale showing the num- 
ber of pounds of butter per creamery inch corresponding 
to different depths of melted butter. While the oil t«st 
is capable of showing the difference between good and 
poor cream, it can not make strictly accurate distinctions 
between different grades of good and of poor cream. 2 As 



1 Refers to paragraph numbers. 

* Wisconsin experiment station, bulletin 12. 



Introduction. 3 

a result, perfect justice cannot be done to different pat- 
rons of creameries where payments for cream delivered 
are made on the basis of this test. 

3. In cheese factories, and since the introduction of the 
centrifugal cream separator, in separator creameries, the 
problem of just payment for the milk furnished by differ- 
ent patrons was no less perplexing than in the case of 
gathered- cream factories. By the pooling system gener- 
ally adopted, each patron received payment in propor- 
tion to the number of pounds of milk delivered, irre- 
spective of its quality. Patrons delivering rich milk 
naturally will not be satisfied with this system when they 
find that their milk is richer than that of their neigh- 
boi's. The temptation to fraudulently increase the 
amount of milk delivered, by watering, or to lower its 
quality by skimming, will furthermore prove too strong 
for some patrons; the fact that it was difficult to prove 
any fraud committed, from lack of a reliable and practi- 
cal method of milk analysis, rendered this pooling system • 
still more objectionable. 

4. As another instance in which the need of a simple 
test for determining the fat content of different kinds of 
milk was strongly felt, may be mentioned the case of pri- 
vate dairymen and breeders of dairy cattle who desired 
to ascertain the butter-producing capacities of the indi- 
vidual cows in their herds. The only manner in which 
this could be done, was by the cumbersome method of 
trial churnings: by saving the milk of the cow to be 
tested, for a day or a week, and churning separately the 
cream obtained. This requires a large amount of work 
when a number of cows are to be tested, and can not 



4 Testing Milk and Its -Products. 

therefore be done except in comparatively few cases, 
with cows of great excellence or by farmers having abun- 
dant hired help. 

5. Introduction of milk tests. The first method which 
fulfilled all reasonable demands of a practical and reli- 
able milk and cream test was theBabcock test, invented by 
Dr. S. M. Babcock, chief chemist to the Wisconsin experi- 
ment station. A description of the test was first pub- 
lished in July, 1890, as bulletin No. 24 of Wisconsin ex- 
periment station, entitled : A new method for the estimation 
of fat in milk, especially adapted to creameries and cheese 
factories. This test, which is now known and adopted in 
all parts of the world where dairying is an important in- 
dustry, was not, however, the first method proposed for 
this purpose which could be successfully operated out- 
side of chemical laboratories. It was preceded by a 
number of different methods, the first one published in 
this country being Short's method, invented by Mr. F. 
G. Short and described in bulletin No. 16 of Wisconsin 
experiment station (July, 1888). 

6. Short's test. la this ingenious method, a certain 
quantity of milk (20 cc. ^ ) was boiled with an alkali solu- 
tion and afterwards with a mixture of sulfuric and acetic 
acids; a layer of insoluble fatty acids separated on top 
of the liquid and was brought into the graduated neck 
of the test bottles by addition of hot water; the reading 
gave the per cent, of fat in the sample of milk tested. 

Short's method did not find very wide application, 
both because it was rather lengthy and its manipulations 
somewhat difficult for non- chemists, and because several 

' See -18, footnote. 



Introduction. 5 

other methods were published shortly after it had been 
given to the public. 

7. Other milk tests. Of these may be mentioned, be- 
sides the Babcock test already spoken of, the Failyer and 
Willard method, ^ Parson's method, 2 Cochran's test, ^ the 
Patrick or Iowa station test, * and the Beimling (Leff- 
mann and Beam) test. ^ Of foreign methods published at 
about the same time, or previously, the Lactocrite, ^ Lie- 
bermann's method, ^ the Schmid, ^ Thorner, ^ I^ahm,^*' and 
Eose-Gottlieb^^ methods may be noted. 

8. All these tests were similar in principle, the solids 
not fat of the milk being in all cases dissolved by the 
action of one or more chemicals, and the fat either meas- 
ured as such in a narrow graduated tube, or brought into 
solution with ether, gasoline, etc., and a portion thereof 
weighed on evaporation of the solvent. While this prin- 
ciple is an old one, having been employed in chemical 
laboratories for many years past, its adaptation to prac- 
tical conditions, and the details as to apparatus and chem- 
icals used were of course new and different in each case. 
The American tests given were adopted to a limited 
extent within the states in which they were originated 

1 Kansas experiment station report, 1888, p. 149. 

2 N. H. experiment station report, 1888, p. 69. 

3 Journal of Anal. Chem., Ill (1889), p. 381. 

4 la. exp. sta., bull. No. 8, February, 1890; Iowa Homestead, June 14, 1889. 

5 Vermont exp. sta., bull. No. 21, September, 1890. For description 
of these and other volumetric methods of milk analysis, see Wiley, Agri- 
cultural Analysis, Vol. Ill, p. 490 et seq; Wing, Milk and its Products, p. 33 
et seq, and Snyder, Chemistry of Dairying, pp. 112-113. 

6 Analyst, 1887, p. 6. 

r Fresenius' Zeitschr., 22, 383. 

8 Ibid., 27, 464. 

9 Chem. Centralbl., 1892, 429. 

10 Milchzeitung, 1894, No. 35; 1897, No. 50. 

11 Landw. Vers. Stat., 40, 1. 



6 Testing Milk and Its Products. 

and even ontside of them, as in case of the Short, Pat- 
rick and Beimling methods. The Babcoek test soon, 
however, nearly everywhere replaced the different meth- 
ods mentioned, and during the past ten years or more it 
has been in practically exclusive use in creameries and 
cheese factories in this country, where payments are 
made on the basis of the quality of the milk delivered, 
as well as in the routine work in experiment station 
laboratories, and among milk inspectors and private 
dairymen. 

9. The Babcoek Test. An examination of the causes 
of the present general adoption of the Babcoek test will 
show the strong points of the test, and the requirements 
made of a practical milk test. The main causes why this 
test has replaced all competitors are doubtless to be 
sought in its simplicity and its cheapness. Its manipu- 
ations are few and readily learned, and it is cheap, both 
in first cost and as regards running expenses. 

The test is fnrthermore speedy, accurate,^ and easily 
applied under practical conditions, and in the opinion of 
the writers it is the very best milk test at our disposal. 

The method is applicable, besides to whole milk, to 
cream, skim milk, butter milk, whey, condensed milk, 
and (if a small scale for weighing out the sample is avail- 
able) to cheese. 

With all its advantages, the Babcoek milk test is not 
in every respect an ideal test. The handling of the very 
corrosive sulfuric acid requires constant care and atten- 



1 For a summary of comparative analyses made by the Babcoek test 
and gravimetric analysis up to 1892, see Hoard's Dairyman, Oct. 7, 1892, p. 
2560; also Schrott-Fiechtl, Milchzeitung, 1896, p. 183 et seq. 



Introduction. 



tionj the speed of the tester, the strength of the acid, the 
temperature of the milk to be tested, and other points, 
always require watching, lest the results obtained be too 
low or otherwise unsatisfactory. In the hands of careful 
operators the test can, however, always be relied upon 
to give most satisfactory results. 

10. Foreign Methods. In European countries four 
practical milk and cream tests, besides the Babcock test, 
are in use at the present time, viz. : Gerber^s acid- 
butyrometer, the lactocrite^ DeLavaV s butyrometer,and Fjord's 
certrifugal cream test. ^ 

Of these the last test 
given has never, to our 
knowledge, been intro- 
duced into this country, 
and the first three only on 
a small scale. 

11. The Gerber method^ 
(fig. 1) is essentially the 
old Beimling method (7), 
worked out independently 
by the Swiss chemist. Dr. 
IsT. Gerber. In this test 
sulfuric acid of the same 
strength is used as in the , 
Babcock test, and a small 
quantity of amyl alcohol is added. The amyl alcohol 
facilitates the separation of the fat, but introduces 




Fig. 1. The Gerber acid- 
butyrometer. 



^ The Lister-Bahcock milk test advertised in English papers and known 
as such in England, is the regular Babcock test, to which the English man- 
ufacturers have prefixed their names; the same applies to the Ahlborn- 
Babcock method and the Krugmann- Babcock method. 

2 Gerber, Die praktische Milchprtifung, 7th edition, 1900. 



8 



Testing Milk and Its Products. 



a source of error which may become serious, when the 
results obtained with a new lot of amyl alcohol can not 
be checked against gravimetric analysis or against 
tests made with amyl alcohol known to give correct 
results. This method is, however, extensively used 
in European countries, having there practically re- 
placed the Babcock test or been adopted in preference 
to it. 

12. The Lactocrite was one of the earliest practical 
milk tests introduced. It was invented by De Laval in 
1886. The acids used in this test are lactic acid (origi- 
nally, acetic acid) with a mixture of hydrochloric and 
sulfuric acids. This test is now but rarely met with. 

13. In the De Laval butyrometer (fig. 2) the same acid 
is used as in the Babcock test, but the tubes employed and 
the manipulations of the method differ materially from 




Fig. 2. De Laval's butyrometer. 



Introduction. 



9 



this test; a smaller sample of milk is taken (only 2 cc. ) 
and a correspondingly small quantity of acid used. Where 
a large number of milk samples are tested every day, 
as is the case, for instance, in European milk control sta- 
tions, the butyrometer may be preferable to the Babcock 
test; but it requires more skill of the operator and does 
not work satisfactorily in case of sour, loppered, or 
partially churned milk. The machine placed on the 
market both by Dr. Gerber and the De Laval Company 
are more expensive than the Babcock testers sold in this 
country; the De Laval test requires a high speed, 5- 6000 
revolutions per minute: and therefore places greater de- 
mands for solidity in the machine than does the Babcock 
test. 

14. Fjord's centrifugal cream tester i (fig. 3) is exten- 
sively used in Dejimark and is mentioned in this connec- 
tion as it furnishes, as a .^ m m .^^ 
rule, a reliable method for 
comparing the quality of 
different lots of milk. The 
method was published in 
1878, by the late K J.Fjord, 
director of the state experi- 
ment station in Copenhagen, 
through whose exertions 
and on whose authority it 
was introduced into Danish creameries in the middle of 
the eighties. No chemicals are added in this test, the milk 
being simply placed in glass tubes, seven inches long 
and about two-thirds of an inch in diameter, and whirled 




Fig. 3. Fjord's centrifugaloream 
tester. 



Instate Danish experiment station, Copenhagen, sixth and ninth re- 
ports, 1885-7. 



10 Testing Milk and Its Products. 

for twenty minutes at a rate of 2000 revolutions per 
minute at 55° (131° F.)- The reading of the cream 
layer thus obtained gives the per cent, of cream, and 
not of butter fat, in the sample tested. One hundred 
and nine-two samples of milk can be tested simultan- 
eously. Within the limits of normal Danish herd milk, 
the results obtained correspond to the percents of fat 
present in the samples, one per cent, of cream being 
equal to about 0.7 per cent, of fatj outside of these limits 
the test is, however, unreliable, especially in case of 
very rich milk and strippers' milk. Only sweet milk 
can be tested by this method. The recent introduction 
of milk tests proper into Denmark, like the Gerber, Bab- 
cock and De Laval tests may, however, in time force the 
Fjord cream test out of Danish creameries, for similar 
reasons that relegated to obscurity the gravity cream 
tests. 1 



1 Among foreign milk tests in use abroad should also be mentioned the 
Wollny Itefraeto'meter,wh]ch, in the bauds of a trained chemist, may prove 
better adapted for use where a very large number of samples are to be 
tested at a time, than any other milk test available. 



OHAPTEE I. 
COMPOSITION OP MILK AND ITS PRODUCTS. 

Before taking up the discussion of the Babcock milk 
test, a brief description of the chemistry of milk and its 
products is given, so that the student may understand 
what are the components of dairy products, and the rela- 
tion of these to each other. Only such points as have a 
direct bearing on the subject of milk testing and the use 
of milk tests in butter and cheese factories or private 
dairies will be treated in this chapter, and the reader is 
referred to standard works on dairying for more detailed 
information in regard to the composition of dairy pro- 
ducts. 

15. Composition of Milk. Milk is composed of the fol- 
lowing substances: water, fat^ casein, albumen, milk sugar, 
and ash. A few other substances are present in small 
quantities, but they are hardly of any practical impor- 
tance and will not be considered here. The components 
of the milk less the water are known collectively as milk 
solids or total solids, and the total solids less the fat, i. e. , 
casein, albumen, milk sugar, and ash, are often spoken 
of as solids not fat or the non-fatty milk solids. The milk 
serum includes all components of the milk less the fatj 
the serum solids are therefore another name for the solids 
not fat; when given, they are, however, generally calcu- 
lated to per cent, of milk serum, not of milk. If, e. g., 
a sample of milk contains nine per cent, of solids not fat, 



12 Testing Milk and Its Products. 

and three per cent, of fat, the milk serum will make up 
97 per cent, of the milk, and the serum solids, -^^t^-^— 
9.28 per cent, of the milk serum. 

16. Water. The amount of water contained in cows' 
milk ranges from 82 to 90 per cent. Normal cows' milk 
will not, as a rule, contain more than 88 per cent, of water, 
nor less than 84 per cent. In states where there are laws 
regulating the sale of milk, as is the case in eighteen states 
in the uaion (see Appendix^Td^A^ll), the maximum limit 
for water in milk in all instances but one (South Carolina) 
is 88 per cent. ; the state mentioned allows 88.5 per cent, 
of water in milk offered for sale within her borders. The 
effect of fraudulently increasing the water content of 
milk 'by watering is considered under Adulteration of 
Milk (118). 

17. Fat. The fat in milk is not in solution, but sus- 
pended as very minute globules, which form an emulsion 
with the milk serum; the globules are present in immense 
numbers, viz., on the average about one hundred millions 
in a single drop of milk; a quart of milk will contain 
about two thousand billions of fat globules, a number 
written with thirteen figures. The size of the globules 
in the milk from the same cows varies according to the 
stage of the period of lactation, the globules being largest 
at the beginning of the lactation period, and gradually 
decreasing in size with its progress. Different breeds of 
cows have fat globules of different average sizes; the 
Channel Island cows are thus noted for the relatively 
large fat globules of their milk, while the lowland 
breeds, the Ayrshire, and other breeds have uniformly 
smaller globules. The diameter of average sized fat 



Composition of Milk and Its Products. 13 

globules in fresh milkers is about 0.004 millimeter, or 
one six- thousandth of an inch; that is, it takes about six 
thousand such globules placed side by side to cover one 
inch in length. The globules in any sample of milk 
vary greatly in size; the largest globules are recovered 
in the cream when the milk is set or run through a cream 
separator, and the smallest ones remain in the skim milk; 
thoroughly skimmed separator skim milk contains only 
a relatively small number of very minute fat globules. 

Milk fat is composed of so-called glycerides of the fatty 
acids, i. e., compounds of the latter with glycerin; some 
of the fatty acids are insoluble in water, viz. , palmitic, 
stearic, and oleic acids, while others are soluble and vol- 
atile, the chief ones among the latter being butyric, cap- 
rylic, and caproaic acids. The glycerides of the insoluble 
fatty acids make up about 92 per cent, of the pure milk 
fat; about 8 per cent, of the glycerides of volatile fatty 
acids are therefore found in natural milk- (and butter-) 
fat. The distinction between natural and artificial but- 
ter lies mainly in this point, since artificial butter (but- 
ter ine, oleomargarine) as well as other solid animal fats 
contain only a very small quantity of volatile fatty acids. 
The glycerides of the volatile fatty acids are unstable 
compounds, easily decomposed through the action of 
bacteria or light; the volatile fatty acids thus set free, 
principally butyric acid, are the cause of the unpleasant 
odor met with in rancid butter. 

Cows' milk generally contains between three and six 
per cent, of fat; in American milk we find, on the 
average, toward four per cent, of fat. The milk from 
single cows in perfect health will occasionally go below 



14 Testing Milk and Its Products. 

or above the limits given, but the mixed milk from a 
whole herd rarely falls outside of these limits. The 
standard adopted by the TJ. S. government for fat in milk 
is 3.25 per ct. The legal standard for fat in milk in most 
states of the Union is 3 per cent. ; Ehode Island allows 
milk containing 2.5 per cent, of fat to be sold as pure, 
while Georgia and Minnesota require it to contain 3. 5 per 
cent, and Massachussetts 3.7 per cent, (in the months of 
May and June; see Appendix, Table IT). 

18. Casein and albumen. These belong to the so-called 
nitrogenous substances, distinguished from the other com- . 
ponents of the milk by the fact that they contain the 
element nitrogen. Another name is albuminoids or protein 
compounds. Casein is precipitated by rennet in the 
presence of soluble calcium salts, and by dilute acids and 
certain chemicals; albumen is not acted upon by these 
agents, but is coagulated by heat, a temperature of 170° F. 
being sufficient to effect a perfect coagulation. The 
casein, with fat and water, form the main components of 
nearly all kinds of cheese. In the manufacture of Ched- 
dar and most other solid cheeses, the casein is coagulated 
by rennet, and the curd thus formed holds fat and whey 
mechanically, the latter containing in solution small 
quantities of non-fatty milk solids. The albumen goes into 
the whey and is lost for cheese making; in some countries 
it is also made into cheese by evaporating the whey under 
constant stirring; whole milk of cows or goats is often ad- 
ded and incorporated into such cheese (primost, gjedost). 

Casein is present in milk partly in solution, in the 
same way as milk sugar, soluble ash- materials an.d albu- 
men, and partly in suspension, in an extremely fine col- 
loidal condition, mixed or combined with insoluble 



Composition of Milh and Its Products. 15 

calcium phosphates. The casein and calcium phosphates 
in suspension in milk may be retained on a filter made 
of porous clay (so-called Ghamberland filters) . 

About 80 per cent, of the nitrogenous compounds of 
normal cows' milk are made up of casein; the rest is 
largely albumen. If the amount of casein in milk be 
determined by precipitation with rennet or dilute acids, 
and the albumen by boiling the filtrate from the casein 
precipitate, it will be found that the sum of these two 
compounds does not make up the total quantity of nitro- 
genous constituents in the milk. The small remaining 
portion (about five per cent, of the total nitrogenous 
constituents) has been called by various authors, globu- 
lin, albumose, hemi-albumose, nuclein, nucleon, proteose, 
etc. The nitrogenous constituents of milk are very un- 
stable compounds, and their study presents many and 
great difficulties; as a result we find that no two scien- 
tists who have made a special study of these compounds 
agree as to their properties, aside from those of casein 
and albumen, or their relation to the nijbrogenous sub- 
stances found elsewhere in the animal body. For our 
purpose we may, however, consider the nitrogen com- 
pounds of milk as made up of casein and albumen, and 
the term casein and albumen, as used in this book, is 
meant to include the total nitrogenous constituents of 
milk, obtained by multiplying the total nitrogen content 
of the milk by 6.25.1 



1 The factor 6.25 is generally used for obtaining the casein and albumen 
from the total nitrogen in the milk, although 6.37 would be more correct, 
since these substances, according to our best authorities, contain on the 

average 15.7 percent, of nitrogen ( = 6.37) 



16 Testing Milk and Its Products. 

The quantity of casein in normal cows' milk will vary 
from 2 to 4 per cent. , and of albumen, from . 5 to . 8 per 
cent. The total content of casein and albumen ranges 
between 2.5 and 4.6 per cent., the average being about 
3.2 per cent. Milk with a low fat content will contain 
more casein and albumen than fat, while the reverse is 
generally true in case of milk containing more than 3. 5 
per cent, of fat. 

19. Mifk sugar or lactose belongs to the group of organic 
compounds known as carbohydrates. It is a commercial 
product manufactured from whey and is obtained in this 
process as pale white crystals, of less sweet taste and less 
soluble in water than ordinary sugar (cane sugar, sucrose). 
About 70 per cent, of the solids in the whey, and 33 per 
cent, of the milk solids, are composed of milk sugar. 

When milk is left standing for some time, viz., from 
one to several days, according to the temperature of the 
surrounding medium, it will turn sour and soon become 
thick and loppered. This change in the composition 
and the appearance of the milk is brought about through 
the action of acid- forming bacteria on the milk sugar. 
These are present in Ordinary milk in immense numbers, 
and under favorable conditions of temperature multiply 
rapidly, feeding on the milk sugar as they grow, and 
decomposing it into lactic acid. When this change alone 
occurs, there is not necessarily a loss in the nutritive 
value of the milk, since milk sugar breaks up directly into 
lactic acid, as shown by the following chemical formula: 
CjgHgjO^j.H^O (lactose) = 4 CgHgOg (lactic acid). ^ 

1 One molecule of milk sugar is composed of 12 atoms of carbon (C), 
22 atoms of hydrogen (H), 11 atoms of oxygen (O), and one molecule of 
water (H 2 O). In the same way, the lactic-acid molecule consists of three 
atoms of carbon, 6 atoms of hydrogen, and 3 atoms of oxygen. 



Composition of Milk and Its I*roducts. 17 

Ordinarily the souring of milk is, however, more com- 
plicated, and other organic bodies, like butyric acid, al- 
cohol, etc., and gases like carbonic acid are formed, re- 
sulting in a loss in the feeding value of the milk. While 
sour milk may therefore contain a somewhat smaller pro- 
portion of food elements than sweet milk, the feeding of 
it to farm animals, especially pigs, will generally pro- 
duce better results than is obtained in feeding similar 
milk in a sweet condition. The cause of this may lie in 
the stimulating effect of the lactic acid of sour milk on 
the appetites of the animals, or in its aiding digestion by 
increasing the acidity of the stomach juices. 

That the souring of milk is due to the activities of 
bacteria present therein is shown clearly by the fact that 
sterile milk, i. e., milk in which all germ life has been 
killed, will remain sweet for any length of time when 
kept free from infection. 

The amount of milk sugar found in normal cows' milk 
varies from 3.5 to 6 per cent., the average content being 
about 5 per cent. ; in sour milk this content is decreased 
to toward 4 per cent. 

20. Ash. The ash or mineral substances of milk are 
largely composed of chlorids and phosphates of sodium, 
potassium, magnesium and calcium; iron oxid and sul- 
furic and citric acids are also present in small quantities 
among the normal mineral milk constituents. The 
amounts of the different bases and acids found in milk 
ash have been determined by a number of chemists; the 
average figures obtained are given in the following table, 
calculated per 100 parts of milk (containing .75 percent, 
of ash) and per 100 parts of milk ash. 
2 



18 Testing Milk and Its Products. 

Mineral Components of Milk. 

In per cent, of Milk. In per cent, of Ash. 

Potassium oxid (K2O) 19 per ct. 25.64 per ct. 

Sodium oxid (NajO) 09 12.45 

Lime (CaO) 18 24.58 

Magnesia (MgO) : 02 3.09 

Iron oxid (FesOg) 002 .34 

Phosphoric anhydrid (P2O 5). .16 21.24 

Chlorin (CI) 12 16.34 

.762 per ct. 103.68 per ct. 

Less oxygen, corresponding to 

chlorin 012 3.68 

.75 100.00 

The combinations in which the preceding bases and 
acids are contained in the milk are not known with cer- 
tainty. According to Soldner, 36 to 56 per cent, of the 
phosphoric acid found in milk, and from 53 to 72 per 
cent, of the lime, are present in suspension in the milk 
as di- and tri- calcium phosphates, and may be filtered 
out by means of Chamberland filters (18), or by long 
continued centrifuging (Babcock^). The rest of the ash 
constituents are dissolved in the milk serum. 

The ash content of normal cows' milk varies but little, 
as a rule only between .6 and .9 per cent., with an aver- 
age of .7 per cent. Milk with a high fat content gen- 
erally contains about .8 per cent, of ash; strippers' milk 
always has a high ash content, at times even exceeding 
one per cent. Ordinarily, the mineral constituents 
are, however, the components of milk least liable to 
variations. 

2L Other Components. Besides the milk constituents 
enumerated and described in the preceding pages, nor- 

1 Wis. experiment station, twelfth report, p. 93. 



Composition of Milk and Its Products. 19 

mal milk contains a number of substances which are 
present in but small quantities and have only scientific 
interest, such as the milk gases (carbonic acid, oxygen, 
nitrogen), citric acid, lecithin, cholesterin, urea, hypo- 
xanthin, lactochrome, etc. 

22. Average Composition. The average percentage 
composition of cows' milk will be seen from table I in 
the Appendix. The following statement shows the limits 
within which the components of normal American cows' 
milk are likely to come: 

Minimum. Maximum. Average. 

Water 82.0perct. 90.0perct. 87.4 per ct. 

Fat 2.3 7.8 3.7 

Casein and albumen 2.5 4.6 3.2 

Milk sugar 3.5 6.0 5.0 

Ash 6 .9 .7 

23. Colostrum Milk. The liquid secreted directly after 
parturition is known as colostrum milk or biestings. It 
is a thick, yellowish, viscous liquid; its high content of 
albumen and ash is characteristic, and also its low con- 
tent of milk sugar. Owing to the large quantity of 
albumen which colostrum contains, it will coagulate on 
being heated toward the boiling point. In the course of 
four to five days the secretion of the udder gradually 
changes from colostrum to normal milk; the milk is con- 
sidered fit for direct consumption or for the manufacture 
of cheese and butter, when it does not coagulate on boil- 
ing and is of normal appearance as regards color, taste, 
and other properties. For composition of colostrum 
milk, see Appendix, Tsihle 1. 

24. Composition of milk products. In addition to its 
use for direct consumption, milk is the raw material from 



20 Testing Milk and Its Products. 

which cream, butter, cheese, and condensed milk are ob- 
tained. 

When milk is left standing for some time or subjected 
to centrifugal force, it will separate into two distinct 
parts, cream Siud sJcim milk. The proportion of each part 
which is obtained and their chemical composition will de- 
pend on the method by which the separation is effected; in 
the so-called gravity process where the cream is separated 
on standing — either in shallow pans in the air, or in deep 
cans, submerged in cold water — a less complete separa- 
tion is reached, less skim milk being obtained and this 
being richer in fat than when the separation takes place 
through the action of centrifugal force. 

In modern creameries the milk is now generally skim- 
med by means of cream separators. Separator cream will 
contain from 15 to 50 per cent, of fat, according to the 
adjustment of the separator and of the milk supply; ordi- 
narily it contains about 25 per ct. of fat. Cream of aver- 
age quality, in addition to the fat content given, consists 
of about QQ per ct. of water, 3.8 per ct. casein and albu- 
men, 4.3 per ct. milk sugar, and .5 per ct. ash. 

The skim milk is made up of the milk serum (15) and a 
small amount of fat, viz., toward .4 per ct. when obtained 
by the gravity process, and less than .2 per ct. in the 
case of separator skim milk. Milk set in shallow pans 
in the air, or in deep cans in water above 60° F., will 
give skim milk containing one-half to over one per ct. of 
fat. Skim milk is used as a food for young farm animals 
or as human food, and in this country only in excep- 
tional cases, for the manufacture of cheese. 

25. Cream is used for the manufacture of butter or for 
direct consumption. In the former case a certain amount 



Composition of Milk and Its Products. 21 

of acidity is generally allowed to develop therein pre- 
vious to the churning process. This secures a more 
complete churning and produces peculiar flavors in the 
butter, without which it would seem insipid to the ma- 
jority of people in this country. Nearly all American 
butter is salted before being placed on the market. Salt 
is a preservative and for a limited length of time pre- 
vents butter from spoiling. Unsalted butter ma'de from 
sweet cream is a common food article in Southern and 
Middle Europe, but only an insignificant amount is man- 
ufactured and consumed in America; salted butter made 
in Europe also contains considerably less salt than Amer- 
ican butter (see Appendix, Table I). Butter contains all 
the fat of the cream but a small portion which goes into 
the butter milk, and a small unavoidable mechanical loss 
incident to the handling of the products. Butter should 
contain at least 80 per ct. of fat and ordinarily contains 
about 83 per ct. ; besides this amount of fat, butter is gen- 
erally composed of water, about 13 per ct., curd and 
milk sugar 1 per ct., and salt 3 per ct. 

Butter milk is similar to skim milk in composition, but 
varies much more than this product, according to the 
acidity, temperature, and thickness of the cream, and 
other churning factors. It contains about 9 per ct. of 
solids, viz., milk sugar (and lactic acid) 4 per ct., casein 
and albumen 4 per ct., fat .3 per ct., and ash .7 perct. 

26. The quantities of butter and by-products obtained 
in the manufacture of butter are as follows: 1000 lbs of 
milk of average quality will give about 850 lbs. of skim 
milk and 145 lbs. of cream (separator slime and mechan- 
ical loss, 5 lbs. ) ; this amount of cream will make about 
42 lbs. of butter and 100 lbs. of buttermilk (mechanical 
loss, 3 lbs.). 



22 Testing Milk and Its Products. 

27. In the manufacture of American cheddar cheese^ 
whole milk is heated to about 86° F.,and a small amount 
of rennet extract is added, which coagulates the casein; 
the albumen of the milk is not precipitated by rennet 
and remains in solution (18). ^'Green" cheese, as taken 
from the press, is made up, roughly speaking, of 37 per 
ct. of water, 34 per ct. of fat, 24 per ct. of albuminoids 
(nearly all casein), and about 5 per ct. of milk sugar, 
lactic acid, and ash (largely salt). In the curing of cheese 
there is some drying off, but the main changes occur in 
the breaking up of the firm curd ipto soluble and digest- 
ible nitrogenous conipounds, peptons, amids, etc. 

Whey is the by-product obtained in the manufacture 
of cheese. It consists of water and less than 7 per ct. of 
solids; of the latter about 5 per ct. is milk sugar, .8 per 
ct. albumen, .6 per ct. ash, and .3 per ct. fat. Whey is 
generally used for feeding farm animals; it is the raw- 
product from which milk sugar and whey cheese are made. 

28. Condensed Milk is manufactured from whole milk 
or from partially skimmed milk. In many brands a large 
quantity of sugar (25 per ct. or more) is added to the 
condensed milk in the process of manufacture so as to 
secure perfect keeping quality in the product. Brands 
to which no sugar has been added are also on the market, 
and in case of such brands the relation between the var- 
ious solid constituents of the condensed milk will be es- 
sentially the same as that between the constituents of 
milk solids. Condensed milk should contain at least 10 
per ct. of fat, and must be free from preservatives and 
all other foreign substances (except sugar). 

Tables are given in the Appendix showing the average 
composition of the various milk products. 



CHAPTEEIL 
SAMPLING niLK. 

29. The butter fat in milk is not in solution, like sugar 
dissolved in water, but the minute fat globules or drops, 
in which form it occurs, are held in suspension in the 
milk serum (17). Being lighter than the serum, the fat 
globules have a tendency to rise to the surface of the milk. 
If, therefore, a sample of milk is left standing for even a 
short time, the upper layer will contain more fat than the 
lower portion. This fact should always be borne in mind 
when milk is sampled. The rapidity with which fat 
rises in milk can be easily demonstrated by allowing a 
quantity of sweet milk to stand in a cylinder or a milk 
can for a few minutes, and testing separately the top, 
middle and bottom layer of this milk. 

The amount of mixing necessary to evenly distribute 
the constituents of milk throughout its mass may be as- 
certained by adding a few drops of cheese color to a quart 
of milk. The yellow streaks through the milk will be 
noticed until it has been poured several times from one 
vessel to another, when the milk will have a uniform 
pale yellow color, Stiring with a stick or a dipper will 
not produce an even mixture so quickly or so complete; 
ly as pouring the milk a few times from one vessel to 
another; in sampling milk for testing it should always 
be mixed by pouring, just before the milk is measured 
into the bottle; if several tests are made of a sample, the 
milk should be poured before each sampling. 



24 Testing Milk and Its Products. 

30. PartiaHy churned milk. A second difficulty some- 
times met with in sampling whole milk arises from the 
fact that a part of the butter fat may be separated in the 
form of small butter granules, by too zealous mixing or 
by reckless shaking in preparing the sample for testing. 
This will happen most readily in case of milk from fresh 
^ows or with milk containing exceptionally large fat 
globules. When some of the butter granules are thus 
churned out, they quickly rise to the surface of the milk 
after pouring and cannot again be incorporated in the 
milk by simple mixing 5 it is, therefore, impossible to 
obtain a fair sample of such milk for testing without tak- 
ing special measures which will be explained in the fol- 
lowing. The granules of butter may be so small as to 
pass into the pipette with the milk and the quantity 
measured thus contain a fair proportion of them, but 
they will be found sticking to the inside of the pipette 
when this is emptied, and thus fail to be carried into the 
test bottle with the milk. 

A similar partial churning of the milk will sometimes 
take place in the transportation cans. When such milk 
is received at the factory, the butter granules are caught 
by the strainer cloth through which the milk is poured, 
and are thus lost both to the factory and to the farmer. 
This separated fat cannot be put into the cream or added 
to the granular butter, without running the risk of mak- 
ing mottled butter, and it will not enter into the sample 
of milk taken for testing purposes. 

When milk samples are sent by mail or express in 
small bottles, or carried to the place of testing, they 
often arrive with lumps of butter floating in the milk or 



Sampling Milk. 25 

sticking to the glass. This churning of the milk can be 
easily prevented by completely filling the bottle or the can. 
If there is no space left for the milk in which to splash 
around, the fat will not be churned out in transit. 

31. Approximately accurate results may generally be 
obtained with a partially churned sample of milk, if a 
teaspoonful of ether be added to it. After adding the 
ether, cork the bottle and shake it until the lumps of 
butter are dissolved. This ether solution of the butter 
will mix with the milk, and from the mixture a fairly 
satisfactory sample may generally be taken. The dilution 
of milk by the ether introduces an error in the testing, 
and only the smallest quantity of ether necessary to dis- 
solve the lumps of butter should be used. If desired, a 
definite quantity of ether, say five per cent, of the vol- 
ume of the sample of milk to be tested, may be added; 
in such cases the result of the test must be increased by 
the per cent, of ether added. 

Example. — To a 4-oz. sample (120 cc.) of partially churned 
milk, 5 per cent., or 6 cc, of common ether are added; the mix- 
ture gives an average test of 4.2 per cent. The test must be in- 
creased by -^1-^x4. 2 =.21, and the original milk therefore con- 
tained 4.2+. 21=4.41 per cent, of fat. 

Milk containing ether must be mixed cautiously with 
acid so as to avoid loss of the contents of the bottle by the 
sudden boiling of the ether due to the heat evolved. 

Instead of adding ether to partially churned samples, 
the milk may be heated to about 110° F. for a few min- 
utes, so as to melt the butter granules; the sample is now 
shaken vigorously until a uniform mixture of milk and 
melted butter is obtained, and a pipetteful then quickly 
drawn from the sample. 



26 Testing Milk and Its Products. 

32. Sampling sour milk. When milk becomes sour, the 
casein is coagulated and the mechanical condition of the 
milk thereby changed so as to render difficult a correct 
sampling. The butter fat is not, however, changed in 
the process of souring; this has been shown by one of us, 
among others, in a series of tests which were measured 
from one sample of sweet milk into six test bottles. 
A test of the milk in one of these test bottles was made 
every month for six months, and approximately the same 
amount of fat was obtained in the tests throughout the 
series, as was found originally in the milk when tested 
in a sweet condition.^ If the milk is in condition to be 
sampled, its souring does not therefore interfere with its 
being tested by the Babcock test or with the accuracy of 
the results obtained. 

In order to facilitate the sampling of sour or loppered 
milk, some chemical may be added which will re- dissolve 
the coagulated casein and produce a uniform mixture that 
ijan be readily measured with a pipette. Any alkali 
(powdered potash or soda, or liquid ammonia) will pro- 
duce this effect. Only a very small quantity of powdered 
alkali is necessary for this purpose. The complete action 
of the alkali on sour milk requires a little time, and the 
operator should not try to hasten the solution by adding 
too much alkali. An excess of alkali will often cause 
such a violent action of the sulfuric acid on the milk to 
which the acid is added (on account of the heat generated 
or the presence of carbonates in the alkali) that the mix- 
ture will be thrown out of the neck of the test bottle when 



1 yee Hoard's Dairyman, April 8, 1892. The same holds true for cream, 
as shown by Winton ( U. S. Dept. Agr., Div. of Chemistry, bull. 43, p. 112). 



Sampling MilJc. 27 

this is shaken in mixing the milk and the acid (37). 
When powdered alkali is, added to the milk, it should be 
allowed to stand for a while, with frequent shaking, until 
the curd is all dissolved and an even translucent liquid 
is obtained. Such milk may become dark -colored by 
the action of the alkali, but this color does not interfere 
with the accuracy of the test. 

Instead of powdered soda or potash, these substances 
dissolved in water (soda or potash lye), or strong am- 
monia water, may be used for the purpose of dissolving 
the coagulated casein in a sample of sour milk. In this 
case, a definite proportion of alkali solution must, how- 
ever, be taken, 5 per cent, of the volume of milk being 
usually sufficient, and the results obtained are increased 
accordingly. (See example cited on p. 25. ) 

33. Sampling frozen milk. When milk freezes, it sep- 
arates into two distinct portions: Milk crystals, largely 
made up of water, with a small admixture of fat and 
other solids, and a liquid portion, containing nearly all 
the solids of the milk. In sampling frozen milk it is 
therefore essential that both the liquid and the frozen 
part be warmed and mixed thoroughly by pouring gently 
back and forth from one vessel into another j the sample 
is then taken and the test proceeded with in the ordinary 
manner (36). 



CHAPTEE III. 

THE BABCOCK TEST. 

34. The Babcock test is founded on the fact that strong 
sulfuric acid will dissolve all non-fatty solid constituents 

of milk and other 
dairy products, and 
will set free the fat. 
This will separate on 
standing, but to effect 
a speedy and complete 
separation, the bottles 
holding the mixture 
of milk and acid are 
placed in a centrifugal , 
machine, a so-called 
tester, and whirled for 
four minutes; hot 
water is then added so 
as to bring the liquid 
fat into the graduated 
neck of the test bot- 
tles, and after a re- 
peated whirling, the 
length of the column 
of fat is read off, show- 
ing the per cent, of fat contained in the sample tested. 




Fig. 4. The first Babcock tester made. 



The Bahcock Test. 29 

Sulfuric acid is preferable to other strong mineral 
acids for the purpose mentioned, on account of its affinity 
to water; when mixed with milk, the mixture heats 
greatly, thus keeping the fat liquid without the applica- 
tion of artificial heat and rendering possible a distinct 
reading of the column of fat brought into the neck of the 
test bottles. 

So far as is known, any kind of milk can be tested by 
the Babcock test. Breed, period of lactation, quality or 
age of the milk is of no importance in using this method, 
so long as a fair sample of the milk can be secured. In 
case of samples of milk or other dairy products rich in 
solids it requires a little more effort to obtain a thorough 
mixture with the acid than with dairy products low in 
solids, like skim milk or whey, which may be readily 
mixed with the acid. 

A. — DiBECTIONS FOR MAKING THE TeST. 

35. The various steps in the manipulation of the Bab- 
cock test are discussed in the following pages; attention 
is drawn to the difficulties which the beginner and others 
may encounter in the use of the test, and the necessary 
precautions to be observed in order to obtain accurate 
and satisfactory results are explained in detail. The 
effort has been to treat the subject exhaustively and from 
a practical point of view, so that persons as yet unfamil- 
iar with the test may turn to the pages of this book for 
help in any difficulties which they may meet in their 
work in this line. 

36. Sampling. The sample to be tested is first mixed 
by pouring the milk from one vessel to another two or 



30 



Testing Milk and Its Products. 



three times so that every portion thereof will 
contain a uniform amount of butter fat (29). 
The measuring pipette which has a capacity of 
17.6 cubic centimeters (see fig. 6), is filled with 
the milk immediately after the mixing is com- 
pleted, by sucking the milk into it until this 
rises a little above the mark around the stem of 
the pipette; the forefinger is 
theu quickly placed over the end 
of the pipette before the milk 
runs down below the mark. By 
slightly releasing the pressure of 
the finger on the end of the 
pipette, the milk is now allowed 
to run down until it just reaches 
the mark on the stem; the quan- 
tity of milk contained in the 
pipette will then, if this is cor- 
rectly made, be exactly 17.6 cc. 
The finger should be dry in 
measuring out the milk so that 
the delivery of milk may be read- 
ily checked by gentle pressure on 
the upper end of the pipette. 

The point of the pipette is 
now placed in the neck of a Bab- 
cock test bottle (fig. 5), and the 
milk is allowed to flow slowly 
down the inside of the neck. Care 
must be taken that none of the 
milk measured out is lost in this 
transfer. The portion of the milk 
remaining in the point of the pip- 
^'''" tefttotu^.""'^^ ette is blown into the test bottle. 



^%mi 



The Bdbcock Test. 



31 



The best and safest manner of holding the bottle and 
the pipette in this transfer is shown in fig. 7. Fig. 8 
shows a position which should be avoided, since by hold- 
ing the bottle in this way, there is danger that some of 
the milk may com- 
pletely fill the neck 
of the bottle, and as a 
result, flow over the 
top of the neck. 

Pipettes, the lower 
part of which slip 
readily into the necks 
of the test bottles, 
may be emptied by 

lowering the pipette J^ into the neck of the bot- 
tle till it rests on its rim, 
when the milk is allowed 
to run into the test 
bottle. 

37. Adding Acid. The 
acid cylinder (fig. 9) 
holding 17. 5 cc, is filled 
to the mark with sulfuric 
acid of a specific gravity 
of 1.82-1.83. This 
amount of acid is care- 
fully poured into the 
test bottle containing the 
milk. In adding the 
acid, the test bottle is conveniently held at an angle 
(see fig. 7), so that the acid will follow the wall of the 
bottle and not run in a small stream into the center of 
the milk, the bottle being slowly turned around and the 




Fig. 7. The right way of emptying 
pipette into test bottle. 



32 



Testing Milk and Its Products. 




neck thus cleared of adhering milk. * By pouring the 
acid into the middle of the test bottle, there is also 
a danger of completely filliug this with acid, in which 
case the plug of acid forfned will be pushed over the 
edge of the neck by the ex- 
pansion of the air in the bot- 
tle, and may be spilled on the 
hands of the operator. 

The milk and the acid in 
the test bottle should be in 
two distinct layers, without 
a black portion of partially 
mixed liquids between them. 
Such a dark layer is often fol- 
lowed by an indistinct separa- 
tion of the fat in the final 
reading. The cause of this 
may be that a partial mixture 
of acid and milk before the 
acid is diluted with the water 
of the milk may bring about 
too strong an action of the . 
acid on the milk, and the fat !. 
in this small por- 
tion maybe slightly 
charred by the 
strong acid. The fig. 8. 
appearance of 
black flocculent matter in or below the column of fat 
which generally results, in either case renders a correct 
measurement of fat difficult and at times even impos- 




The wrong way of emptying pipette 
into test botile. 



The Bahcock Test. 



33 



siblej if the black specks occur in the fat column itself, 
the readings are apt to be too high; if below it, the diffi- 
culty comes in deciding where the column of fat begins. 
38. Mixing milk and acid. After adding the acid, this is 
carefully mixed with the milk by giving the test bottle a 
rotary motion. In doing this, care should be taken that 
none of the liquid is shaken into the neck of the test bottle. 
When once begun, the mixing should be continued until 
completed; a partial and interrupted mixing of the liquids 
will often cause more or less black material 
to separate with the fat when the test is 
finished. Clots of curd which separate at 
first by the action of the acid on the milk, 
must be entirely dissolved by continued and 
careful shaking of the bottle. Beginners 
sometimes fail to mix thoroughly the milk 
and the acid in the test bottle. As the acid 
is much heavier than the milk, a thin layer 
of it is apt to be left unnoticed at the bot- 
_ „ _. tom of the bottle, unless this is vigorously 

Fig. 9. 17 5CC ' & j 

acid cylinder, shaken toward the end of the operation. 

The mixture becomes hot by the action of the acid on 
the water in the milk and turns dark colored, owing to 
the effect of the strong sulfuric acid on the nitrogenous 
constituents and the sugar of milk. 

Colostrum milk or milk from fresh cows will form a 
violet colored mixture with the acid, due to the action 
of the latter on the albumen present in such milk in con- 
siderable quantities (23). 

When milk samples are preserved by means of potas- 
ium bichromate (188), and so much of this material has 




34 Testing Milk and Its Products. 

been added that the milk has a dark yellow or reddish 
color, the mixture of milk and acid will turn greenish 
black, and a complete solution is rendered extremely 
difficult on account of the toughening effect of the bichro- 
mate on the precipitated casein. This difficulty is still 
more pronounced with milk preserved with formalde- 
hyd. 

39. Whirling bottles. After the milk and the acid 
have been completely mixed, the test bottle is at once 
placed in the centrifugal machine or tester and whirled 
for four or five minutes at a speed of 600 to 1200 revo- 
lutions per minute, the proper speed being determined 
by the diameter of the tester (66). It is not absolutely 
necessary to whirl the test bottles in the centrifuge as 
soon as the milk and the acid are mixed, although 
this method of procedure is much to be preferred; 
they may be left in this condition for any reasonable 
length of time (24 hours, if necessary) without the 
test being spoiled. If left until the mixture becomes 
cold, the bottles should, however, be placed in warm 
water (of about 160° F. ) for about 15 minutes before 
whirling. 

Four minutes at full speed is sufficient for the 
first whirling of the test bottles in the centrifuge; 
this will bring all fat to the surface of the liquid in 
the bottle. 

40. Adding water. Hot water is now added by means of 
a pipette or some special device (10 in fig. 58), until the 
bottles ape filled to near the scale on the neck (80). The 
bottles are whirled again at full speed for one minute, 
and hot water added a second time, until the lower part 



The Babcock Test. 



35 



of the column of fat comes within the scale on the neck 
of the test bottle, preferably to the 1 or 2 per cent, 
mark, so as to allow for the sinking of the column of fat, 
due to the gradual cooling of the contents of the bottle. 
By dropping the water directly on the fat in the second 
filling, the column of fat will be washed free from light 
flocculent matter, which might otherwise be entangled 
therein and render the reading uncertain or even too 
high. A final whirling for one 
minute completes the separation of 
the fat. 

41. Measuring the fat. The amount 
of fat in the neck of the bottle is 
measured by the scale or gradua- 
tions on the neck. Each division 
of the scale represents two- tenths of 
one per cent, of fat, and the space 
filled by the fat shows the per cent, 
of butter fafc contained in the sam- 
ple tested. 

The fat is measured from the 
lower line of separation between 
the fat and the water, to the top of 
the fat column, at the point &, 
shown in the figure 10, the reading being thus taken 
from a to h, and not to c or to d. Comparative gravi- 
metric analyses have shown that the readings obtained 
in this manner give correct results. While the lower 
line of the fat column is nearly straight, the upper one 
is curved, and errors in the reading are therefore easily 
made, unless the preceding rule is observed. 



51 






-6 



=_l 






Fig. 10. Measuring the 
column of fat in a Bab- 
cock test bottle. 



36 Testing Milk and Its Products. 

The fat obtained should form a clear yellowish liquid 
distinctly separated from the acid solution beneath it. 
There should be no black or white sediment in or below 
the column of fat, and no bubbles or foam on its surface. 
The bottles must be kept warm until the readings are 
made, so that the column of fat will have a sharply de- 
fined upper and lower meniscus. 

The readings should be made when the fat has a tem- 
perature of about 140° F., although the results obtained 
will not be appreciably affected if the temperature falls 
below 120°. The fat separated in the Babcock test solid- 
ifies at about 100° F. l^o reading should be attempted 
if the fat is partly solidified, as it is impossible to get an 
accurate reading in this case.^ 

42. Eeadings of tests of milk made in steam turbine 
testers with tightly closed covers which prevent the free 
escape of exhaust steam (71) will come . 2 to . 3 per cent, too 
high if the temperature of the fat is allowed to rise to 
that of the exhaust steam during the process of whirling. 
In such cases the test bottles must be allowed to cool to 
about 140° (by placing them in water of this tempera- 
ture for a few minutes) before readings are taken. ^ 



1 The effect of differences in the temperature of the fat on the readings 
obtained will be seen from the following: If 110 and 150° F. be taken as the 
extreme temperatures, at which readings are made, this difference of 40° 
F. (22.3° C.) would make a difference in the volume of the fat column ob- 
tained in case of 10 per cent, milk, of .00064 x 2 x 22.3=. 028544 cc, or .14 per 
cent., .00064 being the expansion coefficient of pure butter fat per degree 
Centigrade between 50 and 100° C{Zune, Analyse des Beurres, I, 87), and 2, the 
volume of the fat in cc. contained in 17.6 cc. of 10 per cent. milk. On 5 per 
cent, milk this extreme difference would therefore be about .07 per cent., 
or considerably less than one-tenth of one per cent. 

2 See Wis. experiment station rep. XVII, p. 76. 



The Bdbcoelc Test. 



37 




Fig. 11. 



A pair of dividers will be found convenienrfor meas- 
uring the fat, and the liability of error in reading 
is decreased by their use. The points 
of the dividers are placed at the upper 
and lower limits of the fat column 
(from a to & in fig. 10). The dividers 
are now lowered, one point being 
placed at the zero mark of the scale, 
and the mark at which the other point 
touches the scale will show the per 
cent, of fat in the sample tested. The 
dividers must be tight in the joint to 
be of use for this purpose. 

42a. A simple device for measuring 
the fat column in the Babcock test has 
been made by Mr. Fred Lutley of Winnipeg Dairy School ^ 
(fig. 11). The instrument consists of two parts: a wooden 
piece, a, sliding inside of &, which is made of tin and is open 
on one side, leaving the corrugated part of a accessible, so 
that this may be raised or lowered with the thumb. A 
steel pointer is attached to each part. The column of fat 
in a test bottle is read off with this instrument in the same 
way as with a pair of dividers. 

B. —Discussion of the Details of the 
Babcock Test. 
43. The main points to be observed as to apparatus 
and testing materials in order to obtain correct and 
satisfactory results by this test will now be considered, 
and such suggestions and help offered, as has been found 
desirable from an extensive experience with a great 
variety of samplesof milk, apparatus, and accessories. 

1 N. Y. Produce Review, April 4, 1903. 



38 Testing Milk and Its Products. 

1. — Glassware. 

44. Test bottles. The test bottles should, have a 
capacity of about 50 cc, or less than two ounces; they 
should be made of well-annealed glass that will stand 
sudden changes of temperature without breaking, and 
should be sufSciently heavy to withstand the maximum 
centrifugal force to which they are likely to be subjected 
in making tests. This force may, on the average, not be 
far from 30. 65 lbs. (see 66), which is the pressure exerted 
in whirling the bottles filled with milk and acid in a 
centrifugal machine of 18 inches diameter at a speed of 
800 revolutions per minute. 

Special forms of test bottles used in testing cream and 
skim milk are described under the heads of cream, and 
skim milk testing (89, 90, 91, 99). 

When 17.6 cc, or 18 grams of milk (48) are measured 
into the Babcock test bottle, the scale on the neck of the 
bottles shows directly the per cent, of fat found in the 
milk. The scale is graduated from to 10 per cent. 
10 per cent, of 18 grams is 1.8 grams. As the specific 
gravity of pure butter fat (i. e. its weight compared 
with that of an equal quantity of pure water) at the 
temperature at which the readings are made (about 140° 
F.), is 0.9, then 1.8 grams of fat will occupy a volume 
of J-^ = 2 cubic centimeters. The space between the and 
10 per cent, marks on the necks of the test bottles must 
therefore hold 2 cc, if correctly made. The scale is 
divided into 10 equal parts, each part representing one 
per cent., and each of these is again sub-divided into 
five equal parts. Each one of the latter divisions there- 



The Bahcoch Test. 39 

fore represents two- tenths of one per cent, of fat when 
17.6 cc. of milk is measured out. The small divisions 
are sufficiently far apart in most Babcock test bottles to 
make possible the estimation of one-tenth of one per 
cent, of fat in the samples tested. 

As the necks of Babcock test bottles vary in diameter, 
each separate bottle must be calibrated by the manufac- 
turers; the length of the scale is not, for the reason given, 
apt to be the same in different bottles. ^ 

If the figures and lines of the measuring scale become 
indistinct by use, the black color may be restored by 
rubbing a soft lead pencil over the scale, or by the use of 
a piece of burnt cork after the scale has been rubbed 
with a little tallow. On wiping the neck with a cloth or 
a piece of paper the black color will show in the etchings 
of the glass, making these plainly visible. 

45. Marking test bottles. Test bottles can now be 
bought with a small band or portion of their neck or 
body ground, or "frosted," for numbering the bottles 
with a lead pencil. Bottles without this ground label 
can be roughened at any convenient spot by using a wet 
fine file to roughen the smooth surface of the glass. There 
is this objection to the latter method that unless carefully 
done, it is apt to weaken the bottles so that they will 
easily break, and to both methods, that the lead pencil 
marks made on such ground labels may be effaced dur- 
ing the test if the bottles are not carefully handled. 



1 A flat-bore test bottle and one with a brass collar and screw used for 
opening and closing a gmall hole in the neck of the test bottle have been 
placed on the market by the Wagner Glass Works of New York. Thpse 
have been tried by us, but no particular advantage over the round- neck 
bottles was 'discovered. 



40 



Testing Mdk and Its Products. 



Small strips of tin or copper with a number stamped 
thereon are sometimes attached as a collar around the 
necks of the bottles. They are, however, easily lost, 
especially when the top of the bottle is slightly broken, 
or at any rate, are soon corroded so that the numbers 
can only be seen with difficulty. 

The best and most permanent label for test bottles is 
made by scratching a number with a marking diamond 
on the glass di- 
rectly above the 
scale on the neck 
of the bottles or 
by grinding a 
number on the 
bottle itself. In 
ordering an out- 
fit, or test bot- 
tles alone, the 
operator may 

specify that the fig. 12. Waste-acid jar. 

bottles are to be marked 1 to 24, or as many as are 
bought, and the dealer will then put the numbers on 
with a marking diamond. 

A careful record should be kept of the number of the 
bottle into which each particular sample of milk is meas- 
ured. Mistakes are often made when the operator trusts 
to his memory for locating the different bottles tested at 
the same time. 

46. Cleaning test bottles. The fat in the neck of the 
test bottles must be liquid when these are cleaned. In 
emptying the acid the bottle should be shaken in order 




The Bahcoch Test. 



41 



to remove the white residue of sulfate of lime, etc., from 
the bottom; if the acid is allowed to drain out of the 
bottle without shaking it, this residue will be found to 




Fig. 13, Apparatus for cleaning test bottles. A, apparatus in position; 
the water flows from the reservoir through the iron pipe & into the in- 
verted test bottle d through the brass tube c, screwed into the iron pipe. 
B shows construction of the rubber support on which the tops of the test 
bottles rest; /, draining sink. 

stick very tenaciously to the bottom of the bottle in the 
subsequent cleaning with water. 

A convenient method of emptying test bottles is shown 
in the illustration (fig. 12). After reading the fat col- 



42 



Testing Milk and Its Products. 



umn, the bottles are placed neck down, in the half- inch 
holes of the board cover of a five-gallon stoneware jar. 
An occasional shaking while the liquid is running from 
the bottles will rinse off the precipitate of sulfate of 
lime. A thorough rinsing with boiling hot water by 
means of an apparatus, devised by one of us^ (see fig. 13), 
is generally sufficient to remove all grease and dirt, as 
well as acid solution Jrom the inside of the bottles. 
When the bottles have been rinsed, they are placed in 
an inverted position to drain, on a galvanized iron rack, 
as shown in fig. 14, where they are kept until needed. 
The outside of the 
bottles should occa- 
sionally be wiped 
clean and dry. 

47. The amount of 
unseen fat that clings 
to test bottles used 
for testing milk or cream, is generally not sufficient to 
be noticed in testing whole milk, but it plays an im- 
portant part in testing samples of separator skim milk. 
It may be readily brought to light by making a blank 
test with clean water in bottles used for testing ordinary 
milk, which have been cleaned by simply draining the 
contents and rinsing once or twice with hot water; at the 
conclusion of the test the operator will generally find that 
a few drops of fat — sometimes enough to condemn a 
separator — will collect in the neck of the bottles. 

Boiling hot water will generally clean the grease from 
glassware for a time, but all test bottles should, in addi- 




FiG. 14. Draining-rack for test bottles. 



1 Farrington. 



The Babcoch Test 



43 




Fig. 15. Tank for cleaning test bottles. 



tion, be given an 
occasional bath in 
some weak alkali 
or other grease- 
dissolving solution. 
Persons doing con- 
siderable milk test- 
ing will find ifc of 
advantage to pro- 
vide themselves 
with a small cop- 
per tank, which 
can be filled with a 
weak alkali-solu- 
tion (figs. 15 and 
16). After having 
been rinsed with 
hot water, the test 



bottles are placed in the hot solution in the tank, where 
they may be left completely covered with the liquid. If 




Fig 16. Rack for holding test bottles in tank shown in fig. 15. 



44 * Testing Milk and Its Products. 

the tank is provided with a small faucet at the bottom, 
the liquid can be drawn off when the test bottles are 
wanted. A tablespoonful of some cleaning powder to 
about two gallons of water will make a very satisfactory- 
cleaning solution; sal soda, Gold Dust, Lewis'' lye or Bdb- 
MtPs potash are very efficient for this, purpose. The 
cleansing properties of solutions of any of these substances 
are increased by warming the liquid. The test bottles 
must be rinsed twice with hot water after they are taken 
from this bath. 

The black stains that sometimes stick to the inside of 
test bottles after prolonged use, can be removed with a 
little muriatic acid. 

An excellent cleaning solution may be made of one- 
half pound bichromate of potash to one gallon of sul- 
furic acid (Michels, Am. CheesemaJcer, Jan. 1903). 

48. Pipette. The difference in the weights of various 
samples of normal milk generally falls within compara- 
tively narrow limits; if a given volume of water weighs 
one pound, the same volume of the usual grades of nor- 
mal milk will weigh from 1.029 to 1.033 pounds, or on 
the average, 1.03 lbs. 18 grams of water measures 18 
cc.^; 18 grams of milk will therefore take up a smaller 
volume than 18 cc, viz: 18 divided by 1.03, which is 
very nearly 17.5. This is the quantity of milk taken 
in the Babcock test. A certain amount of milk will ad- 
here to the walls of the pipette when it is emptied, and 

1 Cubic centimeters (abbreviated: cc.) are the standard used for meas- 
uring volume in the metric system, similar to thequart or pint measure 
in our ordinary system of measures. One quart is equal to a little less than 
1,000 cubic centimetei'S. In the same way, grams represent weight, like 
pounds and ounces. One cc. of water at 4° Centigrade weighs 1 gram; 1,000 
grams (=1 kilogram) are equal to 2.2 lbs. Avoirdupois. (See Appendix for 
Comparisons of metric and customary weights and measures.) 



The Babeock Test. 



45 




A 



B 



Fig. 17. Pip- 
ette points — 
A, proper con- 
struction; B, 
undesirable 
construction 



this thin film has been found to weigh about one tenth 
of a gram; consequently 17.6 cc. has been adopted as the 
capacity of the pipette used for delivering 
18 grams of milk. 

For convenience in measuring the milk, 
the shape of the pipette is of importance. 
The mark on the stem should be two inches 
or more from the upper end of the pipette. 
The lower part should be small enough to fit 
loosely into the neck of the test bottle, and not 
contracted to a fine hole at the point; the 
point should be large enough to allow a 
quick emptying of the pipette (fig. 17). 

49. Fool Pipettes. Soon after the Babcock test began to be 
generally used at creameries as a method of paying for the milk, 
a creamery supply house put on the market a 20 cc. milk-meas- 
uring pipette, which was claimed to show the exact butter 
value of milk, instead of its content of butter fat as is the case 
in using the ordinary 17.6 cc, pipette. A 20 cc. pipette will 
deliver 2.4 cc. more milk than a 17.6 cc. pipette, (or 13.6 per 
cent, more), and the results obtained by using these pipettes 
will, therefore, be about 13.6 per cent, too high. In consider- 
ing the subject of Overrun (214) it is noted that the excess of 
butter yield over the amount of fat contained in a certain quan- 
tity of milk will range from about 10 to 16 per cent., or on the 
average, about 12 per cent. 20 cc. pipettes may, therefore, give 
approximately the yield of butter obtained from a quantity of 
milk, but as will be seen, this yield is variable, according to the 
skill of the butter maker and according to conditions beyond his 
control; it cannot therefore be used as a standard in the same 
manner as the fat content of the milk. Similar 22 cc. pipettes 
were also sent out. These pipettes created a great deal of con- 
fusion during the short time they were on the market, and 
were popularly termed "fool pipettes." It is not known that 
any of these pipettes have been sold of late years. 



46 Testing Milk and Its Products. 

A recent Wisconsin law makes it a misdemeanor to use other 
pipettes than 17.6 cc. ones for measuring milk where this is paid 
for by the Babcock test.^ 

50. Acid measures. A 17.5 cc. glass cylinder (fig. 9) 
for measuring the acid is generally included in the outfit, 
when a Babcock tester is bought. This cylinder answers 
every purpose if only occasional tests are made; the acid 
is poured into the cylinder from the acid bottle as 
needed, or a quantity of acid sufficient for the number of 
test bottles to be whirled at a time, is poured into a small 
glass beaker provided with a lip, or into a small porce- 
lain pitcher; these may be more easily handled than the 
heavy acid bottle, and the acid measure is then filled 
from such a vessel. 

Where a considerable number of tests are made regu- 
larly, the acid can be measured into the test bottles 
faster and with less danger of spilling, by using some one 
of the many devices proposed for this purpose. There 
is some objection to nearly all of these appliances, auto- 
matic pipettes, burettes, etc., although they will often 
give good satisfaction for a time while new. Sulfuric 
acid is very corrosive, and operators as a rule take but 
poor care of such apparatus, so that it is a very difficult 
matter to design a form which will remain in a good work- 
ing order for any length of time. Automatic pipettes 
attached to acid bottles or reservoirs, to prove satisfac- 
tory, must be made entirely of glass, and strong, of sim- 
ple construction, tightly closed and quickly operated. 

51. The Swedish acid-bottle answers these requirements 
better than any other device known to the writers at the 
present time. Its use is easily understood (see fig. 18); 
it gives good satisfaction if the hole in the glass stop 

iLaws of 1903, chapter 43. 



The Bahcock Test. 



47 





ACID BOTTUt-ti 




cock through which the acid passes has a diameter of at 
least ODC-eighth of an inch, as is generally the case. We 
have used or inspected some half a 
dozen other devices, which have 
been placed on the market by vari- 
ous dealers for delivering the acid, 
but cannot recommend them for 
use in factories or outside of chem- 
ical laboratories. 

52. Instead of measuring out the 
acid, Bartlett ^ suggested adding it 
directly to the milk in the test bot- 
tles, till the mixture rises to a mark 
on the body of the bottle at the 
point where this will hold 37.5 cc, 
i. e., the total volume of milk and 
acid (89). This method of adding 
the acid is in the line of simplicity, 
but has not become generally 
adopted. If the method is used the marks should be put 
on by the manufacturers, as the operator in attempting 
to do so will be apt to weaken or break the bottles. 
Calibration of Glassware. 
Test Bottles. The Babcock milk test bottles are so 
constructed that the scale or graduation of the neck 
measures a volume of 2 cubic centimeters, between the 
zero and the 10 per cent, marks (44). The correctness 
of the graduation may be easily ascertained by one of the 
following methods: 

53. (A.) Calibration with mercury. 27.18 grams of 
metallic mercury are weighed into the perfectly clean 

1 Maine experiment station, bull. No. 31. 



Fig. 18. Swedish acid-bot- 
tle; the side tube is made 
to hold 17.5 cc. of acid. 



48 Testing Milk and Its Products. 

and dry test bottle. Since the specific gravity of mer- 
cury is 13. 59, double this quantity will occupy a volume 
of exactly 2 cubic centimeters (48). The neck of the 
test bottle is then closed with a small, smooth and soft 
cork, or a wad of absorbent cotton, cut off square at one 
end, the stopper being pressed down to the first line of 
the graduation. The bottle is now inverted so that the 
mercury will run into its neck. If the total space in- 
cluded between the and 10 marks is just filled with the 
two cubic centimeters of mercury, the graduation is cor- 
rect. Bottles, the whole length of the scale of which 
vary more than two-tenths of one per cent., are inaccu- 
rate and should not be used. 

The mercury may be conveniently transferred from one 
test bottle to another, by means of a thin rubber tube 
which is slipped over the end of the necks of both bot- 
tles, and one weighing of mercury will thus suffice for a 
number of calibrations. In transferring the mercury, 
care must be taken that none of it is lost, and that small 
drops of mercury are not left sticking to the walls of the 
bottle emptied. A sharp tap on the bottle with a lead 
pencil will help to remove minute drops of mercury from 
the inside. Unless the bottles to be calibrated are per- 
fectly clean and dry, it is impossible to transfer all the 
mercury from one bottle to another. 

After several calibrations have been made, the mercury 
should be weighed again in order to make certain 
that none has been lost by the various manipulations. 
The scales, figs, 34 and 35, shown in (91), are sufficiently 
delicate for making these weighings. 

54. Cleaning mercury. Even with the best of care, 
mercury used for calibration of glassware will gradually 



The Babcock Test. 49 

become dirty, so that it will not flow freely over a clean 
surface of glass. It may be cleaned from mechanical 
impurities, dust, films of grease, water, etc., by filtration 
through heavy filter paper. This is folded the usual 
way, placed in an ordinary glass funnel and its point 
perforated with a couple of pin holes. The mercury will 
pass through in fine streams, leaving the impurities on 
the filter paper. Mercury may be freed from foreign 
metals, zinc, lead, etc., sometimes noticed as a grayish, 
thin film on its surface, by leaving it in contact with 
common nitric acid for a number of hours; the mercury 
is best placed in a shallow porcelain or granite ware dish 
and the nitric acid poured over it, the dish being covered 
to keep out dust. The acid solution is then carefully 
poured off and the mercary washed with water; the latter 
is in turn poured off, and the last traces of water absorbed 
by means of clean, heavy filter paper. 

The mercury to be used for calibration of glassware 
should be kept in a strong bottle, closed by an ordinary 
stopper. In handling mercury, care must be taken not 
to spill any portion of it; finger-rings should be removed 
when calibrations with mercury are to be made. 

Mercury forms the most satisfactory and accurate ma- 
terial for calibration of test bottles, on account of its 
heavy weight and the ease with which it may be manip- 
ulated. Equally correct results may, however, with 
proper care be obtained by using water for the calibration. 

(B.) Calibration with water. This may be done by 
means of a delicate pipette or burette, or by weighing in 
a somewhat similar manner, as explained in case of cali- 
bration with mercury. 
4 



50 Testing Milk and Its Products. 

55. a, Measuring the Water. Fill the test bottle with 
water to the zero mark of the scale; remove any surplus 
water and dry the inside of the neck with a piece of filter 
paper or clean blotting paper; then measure into the 
bottle 2 cc. of water from an accurate pipette or burette, 
divided to ^V ^^ ^ cubic centimeter. If the graduation 
is correct, 2 cc. will fill the neck exactly to the 10 per 
cent, mark of the scale. 

56. b, Weighing the water. Fill the bottle with water 
to the zero mark of the scale and remove any surplus 
water in the neck, as before. Weigh the bottle with the 
water contained therein. Now fill the neck with water 
to the 10 per cent, mark, and weigh again. The differ- 
ence between these weights should be 2 grams. 

In all cases when calibrations are to be made, the 
test bottles, or other glassware to be calibrated, must be 
thoroughly cleaned beforehand with strong sulfuric acid 
or soda lye, and washed repeatedly with pure water, 
and dried. Glassware is not clean unless water will 
run freely over its surface, without leaving any ad- 
hering drops. 

57. (C. ) The Trowbridge method of calibration.^ An 
extremely simple and accurate method of calibrating test 
bottles has been proposed by Mr. O. A. Trowbridge of 
Columbus, Wis. He conceived the idea of measuring the 
capacity of the graduated portion of the neck of a milk 
test bottle with a piece of metal which is carefully filed 
to such a size that it will displace exactly two cubic centi- 
meters of water. He used a thirty-penny wire nail, cutting 
off the head of the nail and attaching to it a short piece 

1 Hoard's Dairyman, Mar. 8, 1901, by De Witt Goodrich. 



The Babcoclc Test 



51 



h 



of fine wire, either looped at one end, as shown in fig. 19 
(A), or as one straight piece of about three inches long. 
The wire serves as a handle for lowering the measure 
into the neck of the test bottles. If the wire is attached 
as shown in fig. 19 (A), a string can be fastened to the 
loop for holding the measure in the proper place in the 
test bottle. 

When a test bottle is to be calibrated by this standard 
measure, it is filled wich water to the zero mark on the 

neck of the bottle. The 
water adhering to the neck 
is carefully removed with 
a strip of blotting paper, 
and the measure (A) is then 
lowered into the test bottle, 
as shown in (B), to the point 
where the wire loop is at- 
tached. If the water rises 
from to 10 on the neck 
when the point of the meas- 
ure is also at ten, the scale is 
correct. If greater varia- 
tions than .2 of one per cent, 
occur, the bottle should be 
rejected. 

The figure (0), shows one 
of these calibrators made in 
two sections, so that the accu- 
racy of the 5 as well as the 10 mark on the scale may be 
ascertained. This modification was proposed by Louis 
F. Nafis&Co., Chicago. 



B 



Fia. 19. (A) Trowbridge cali- 
brator as used in test bottle (B). 
(C) Nafls modification of (A). 



52 Testing Milk and Its Products. 

58. The standard measure. In the place of an iron 
nail a piece of copper or glass rod may be advanta- 
geously used as a standard measure. The standardization 
is most conveniently, done by weighing. Since the specific 
gravities of iron, copper and glass are 7.8, 8.9, and about 
2.7, respectively, pieces of these materials replacing 2 cc. 
of a liquid, will weigh 15.6, 17.8 and 5.4 grams, for iron, 
copper and glass in the order given. 

A measure of the right weight may be suspended by a 
very fine copper or platinum wire (melted into the glass 
rod if this material be chosen), and is used directly for 
calibrating test bottles as described above. Before a 
measure so made is used as a standard, its accuracy 
should be determined by weighing the amount of water 
at a temperature of 17.5° 0, which it replaces. The 
specific gravity of glass especially, varies somewhat ac- 
cording to its composition, so that a standardization of a 
measure by. weight alone cannot be depended upon al- 
ways to give correct results. 

59. In submerging the measure in the test bottle to be 
calibrated, care must be taken that all air bubbles are 
removed before the position of the meniscus of the water 
is noted; if a metal standard measure is used, it must be 
kept free from rust or tarnish. 

60. Intermediate divisions. The space between and 
10 on the scale of the Babcock test bottle is divided into 
50 divisions, each five of which, as previously shown, 
representing 1 per cent. (44). Since these intermediate 
divisions are generally made with a dividing machine, 
they are as a rule correct, but it may happen that the 
divisions have been inaccurately placed, although the 



The Babcock Test. 53 

space between the 10 is correct. The accuracy of the 
intermediate divisions can be ascertained by sliding 
along the scale a strip of paper upon which has been 
marked the space occupied by one per cent., and com- 
paring the space with those of e^iCh per cent, on tlie 
scale. 

61. Calibration of skim mifk test bottles. The value of 
each division on the skim milk bottles is one twentieth 
of one per cent. (99); there are ten of these divisions 
or .1 cc. in the whole scale which shows .5 per cent, 
fat. It requires very careful work to calibrate this scale 
and it is best done by weighing the amount of mercury 
which will just fill the space between the first and the 
last divisions (53); the correct weight of this mercury 
"is 1.359 grams. 

62. Calibrating Cream test bottles. The cream bottles 
may be calibrated by any of the methods given for milk 
bottles. A cream test bottle neck that measures thirty 
per cent, fat will hold 6 cc, and 6 grams of water or 
81.54 grams of mercury. 

The Trowbridge method of calibrating milk test bot- 
tles may also be found convenient for cream bottles and 
the same standard measure used. The part of the scale 
from to 10 being calibrated first, then from 10 to 20, 
and from 20 to 30 per cent, in the same way. 

63. Pipette and acid cylinder. The pipette and the 
acid cylinder used in the Babcock test may be calibrated 
by any of the methods already given. Sufficiently 
accurate results are obtained by weighing the quantity 
of water which each of these pieces of apparatus will 
hold, viz., 17.6 grams and 17. 5 grams, respectively. The 



54 - Testing Milh and Its Products. 

necessity of previous thorough cleaning of the glassware 
is evident from what has been said in the preceding. 
The pipette and the acid, measure may be weighed empty 
and then again when filled to the mark with pure water, 
or the measure ful of water may be emptied into a small 
weighed vessel, and this weighed a second time. In 
either case the weight of the water contained in the 
pipette or acid measure is obtained by difference.^ 

Calibrations of the acid cylinder are generally not 
called for, except as a laboratory exercise, since small 
variations in the amount of acid measured out do not 
affect the accuracy of the test. 

2. — Centrifugal Machines. 

64. The capacity of the testing machine to be selected 
should be governed by the number of tests which are 
likely to be made at one time. For factory purposes a 
twenty-four or a thirty -two bottle tester is large enough, 
and to be preferred for a larger tester, even if toward a 
hundred samples of milk are to be tested at a time. The 
operator can use his time more economically in running 
a machine of this size than one holding fifty or sixty bot- 
tles; the work of filling or cleaning the bottles and 
measuring the fat can be done while the tester is running 
if a double supply of bottles is at hand. Large testers 
require more power than smaller ones, and when sixty 
tests are made at a time, the fat column in many bottles 



1 1 Cubic centimeter of distilled water weighs 1 gram, when weighed in 
a vacuum at the temperature of the maximum density of water (4° C); for 
the purpose of calibration of glassware used in the Babcock test, suf- 
ficiently accurate results are, however, obtained by weighing the water in 
the air and at a low room temperature (60° F.)- 



The Bahcock Test 55 

will get cold, before the operator has time to read them, 
unless special precautions are taken for keeping the bot- 
tles warm. 

65. The tester should be securely fastened to a solid 
foundation and set so that the revolving wheel is level. 
The latter must be carefully balanced in order that the 
tester may run smoothly at full speed when empty. A 
machine that trembles when in motion is neither sat- 
isfactory nor safe, and the results obtained are apt to 
be too low. High- standing machines are more apt to 
cause trouble in this respect than low machines, and 
should therefore be subjected to a severe test before 
they are accepted. 

If all the sockets are not filled with bottles when a test 
is to be made, the bottles must be placed diametrically 
opposite one another so that the machine will be balanced 
when ran. The bearings should be kept cleaned and 
oiled with as much care as the bearings of a cream 
separator. 

The cover of the machine should always be kept closed 
while the bottles are whirled, and should not be removed 
until the machine stops; it should be tight fitting and 
may be fastened with hooks soldered on the side of 
the machine; test bottles sometimes break while the 
machine is running at full speed, and every possible pre- 
caution should be taken to protect the operator from any 
danger from spilled acid or broken glass. 

66. Speed required for the complete separation of the 
fat. There is a definite relation between the diameter of 
the Babcock testers and the speed required for a perfect 
separation of the fat. In the preliminary work with the 



56 Testing Milk and Its Products. 

Babcock test the inventor found that with the machine 
used, the wheel of which had a diameter of eighteen 
inches, it was necessary to turn the crank, so as to give 
the test bottles §even or eight hundred revolutions per 
minute, in order to affect a maximum separation of fat; 
later work has shown that this speed is ample. Taking 
therefore this as a standard, the centrifugal force to which 
the contents of the test bottles are subjected when sup- 
ported on an eighteen-inch wheel and turned 800 revolu- 
tions per minute, can be calculated as follows: 

The centrifugal force, F, acting on the bottles is expressed by 
the formula 

^-^2:2F (I) 

in which w = the weight of the bottle with contents, in pounds; 
V = the velocity, in feet per second, and r = the radius of the 
wheel in feet. 

When the wheel is turned 800 times a minute, a bottle sup- 
ported on its rim will travel 27rrx«6"(? = ^xS.UlSXf^X^V =62.83 
feet per second. The weight of a bottle, with milk and acid, is 
about 3 ounces, or ^^ of a pound. Substituting these values 
for V and w, gives 

Ax 62. 832 

The bottles are therefore, under the conditions given, sub- 
jected to a pressure of about 30:65 pounds. In order to calculate 
the speed required for obtaining this force in case of machines 
of other diameters, the value of v in formula (I) is found from 



^^ / 32.2Fxr ^ . . . (II) 
[/ w 



Substituting the values for F and w, 

_ /32.2 X 30.65 r_ 

V — i^ 



5264 r 



1 6 

In this equation the values r = 5, 6, 7, 8, 9, 10, 11, 12 inches 
are substituted in each case (^4' i\' tV' • • • "H^®®^)' and the 



The Bahcock Ted. 57 

velocity in feet per second then found at which the bottles are 
whirled when placed in wheels of diameters 10 to 24 inches, and 
subjected in each case to a centrifugal force of 30.65 lbs. As the 

number of revolutions per minute — ^ ^ . v being as before 

27rr 

the velocity in feet per second, and r the radius of the wheel, 
the speed at which the wheel must be turned, is found by sub- 
stituting for V the values obtained in the preceding calculations 
in case of wheels of different diameters. The results of these 
calculations are given in the following table: 



Diameter 
of wheel, D. 

10 


Velocity infect 
per second, v. 

46.84 


Number af revolutions 
of wheel per minute. 

1074 


12 


51.31 




980 


14 


55.43 




909 


16 


59.26 




848 


18 


62.84 




800 


20 


66.24 




759 


22 


69.47 




724 


24 


72.56 




693 



These figures show that a tester, for instance, 24 inches in 
diameter, requires less than 700 revolutions per minute for a 
perfect separation of the fat in Babcock bottles, while a ten- 
inch tester must have a speed of nearly 1100 revolutions, in 
order to obtain the same result. 

The speed at which testers of different diameters should be 
run to effect a complete separation has been calculated by Prof. 
C. L. Beach in the following manner.^ The same standard as 
before is taken, viz., 800 revolutions for an 18-inch tester (radius 
9 inches); then if a; designate the radius of the tester and y the 
speed required, we have 

xy-=9x8002, or 



^_ /9 X 8002 

The figures obtained by the use of this formula are similar to 
those given in the preceding table. 



1 Private communication. 



58 Testing Milk and Its Products. 

67. To find the number of turns of the handle corres- 
ponding to the number of revolutions made by the wheel, 
the handle is given one full turn, and the number of 
times which a certain point or part of the wheel revolves, 
is noted. If the wheel has a diameter of 20 inches, and 
revolves 12 times for one turn of the handle, the latter 
should be turned -^^=63 (see table), or about once every 
second, in order to effect a maximum separation of fat. 
By counting the number of revolutions, watch in hand, 
and consulting the preceding table, the operator will 
soon note the speed which must be maintained in case of 
his particular machine. It is vitally important that the 
required speed be always kept up; if through careless- 
ness, worn-out or dry bearings, low steam pressure, etc., 
the speed is slackened, the results obtained will be too 
low; it may be a few tenths, or even more than one per 
cent. Care as to this point is so much the more essen- 
tial, as the results obtained by too slow whirling may 
seem to be all right, a clear separation of fat being often 
obtained even when the fat is not completely separated. 

68. Ascertaining the necessary speed of testers. In 
buying a tester the operator should first of all satisfy 
himself at what speed the machine must be run to give 
correct results: the preceding table will serve as a guide 
on this point. He should measure out a dozen tests of 
the same sample of milk, and whirl half the number at 
the speed required for machines of the diameter of his 
tester. Whirl the other half at a somewhat higher 
speed. If the averages of the two sets of determinations 
are the same, wi bin the probable error of the test (say, 
less than one-tenth of one per cent. ) the first whirling 



The Babcock Test. 59 

was sufficient, as it is believed will generally be the case. 
If the second set of determinations come higher than the 
first set, the first whirling was too slow, and a new series 
of tests of the same sample of milk should be made to 
ascertain that the second whirling was ample. 

This method will test not only the speed required with 
the particular machine at hand, but will also serve to 
indicate the correctness of the calibration of the bottles. 
A large number of tests of the same sample of milk 
made as directed (pouring the milk once or twice previ- 
ous to taking out a pipetteful for each test) should not 
vary more than two-tenths of one per cent, at the outside, 
and in the hands of a skilled operator will generally 
come within one-tenth of one per cent. If greater dis- 
crepancies occur, the test bottles giving too high or too 
low results should be further examined, and calibrated 
according to the directions already given (53 et seq.). 

69. Hand testers. When only a few tests are made at 
a time, and at irregular intervals, as in case of dairymen 
who test single cows in their herds, a small hand tester 
answers every purpose. These may be had in sizes from 
two to twelve bottles. In selecting a particular make of 
tester the dairyman has the choice of a large number of 
different kinds of machines. It is a source of regret that 
most of the early machines placed on the market for this 
purpose were so cheaply and poorly constructed as to 
prove very unsatisfactory after having been in use for a 
time. The competition between manufacturers of dairy 
supplies and the clamor of dairymen for something 
cheap, fully accounted for this condition of affairs. This 
applies especially to the many machines made with belts 



60 



Testing Milk and Its Products. 




or friction application of power. The main objection to 
such machines is the uncertainty of the speed obtained, 

when they have 
been in use for 
some time, and 
the belt or fric- 
tion appliance 
begins to slip. 
Hand testers 
made with cog- 
geared wheels 
are more to be 
depended on for 
giving the nec- 
essary speed 
than belt or fric- 

FiG.21. Type of Babcock hand testers. ^.^^ machines; 

the earlier machines 
of this kind were 
very noisy, but at the 
present time the best 
machines on the mar- 
ket are of this type. 
These are provided 
with spiral cog- gear- 
ing and ball bearings, 
are strongly made and 
will run smoothly and 

without noise (figs. 21 ^^^- ^' '^^^^ °^ Babcock hand testers. 

and 22); in cog-geared machines the bottles are always 
whirled at the speed which the number of turns made 
by the crank would indicate. 




The Babcock Test. 



61 



70. Power testers. For factory purposes, steam tur- 
bine machines (figs. 23-25) are most satisfactory when 

well made and well cared 
for. They should always 
be provided with a speed 
indicator and steam 
gauge, both for the pur- 
pose of knowing that suf- 




FiG. 23. Type of Babcock steam 
turbine testers. 




Fig. 24. Type of Babcock steam turbine testers. 

ficient speed is attained, and also to prevent what may 
be serious accidents from a general smash-up, if the tur- 



62 



Testing Milk and Its Froducts. 



bine '^runs wild" by turning on too much gteam. The 
revolving wheel of the tester should be made of wrought 
or malleable iron, or of wire, so that it will not be broken 
by the centrifugal force, thus avoiding serious accidents. 

The swinging pock- 
ets which hold the 
test bottles in some 
machines, should 
be so made that the 
bottles will not 
strike the center of 
the revolving 
frame when in a 
; horizontal position. 
Tests have often 
been lost by the 

FIG. 25. Type of Babcock turbine testers. ^^^ ^^ ^-^^ ^^^^ 

catching at the center, the bottles thus failing to take 
an upright position when the whirling stops. 

71. The exhaust steam pipe of turbine testers should 
not have too many turns in it or be much reduced in size 
from that of the opening in the tester. A free escape of 
the exhaust steam is necessary to prevent the steam col- 
lecting in the test bottle chamber and overheating the 
test bottle when whirled (41). 

The cover of the tester should have an opening pro- 
vided with a sliding damper or some arrangement by 
which it can be closed when desired. If whole milk or 
cream is being tested, this hole should be open so that a 
draft of air may enter the test bottle chamber during 
whirling, and force the steam out of the bottle chamber 




The Babcock Test. 63 

into the exhaust pipe. If skim milk is being tested, the 
opening in the cover should be closed. This shuts off 
the draft of air, and the exhaust steam heats the test 
bottles during whirling to 200° F. in some cases. This 
high temperature aids in separating the last traces of fat 
in skim milk and gives a most accurate test of samples 
containing less than one- tenth per cent. fat. Some of 
the most recent makes of turbine testers are provided 
with holes in the cover and dampers. A thermometer 
is also placed in the cover. 

3. — Sulfuric Acid. 

72. The sulfuric acid to be used in the Babcock test 
should have a specific gravity of 1.82-1.83.^ The com- 
mercial oil of vitriol which can be bought for about 
2 cents a pound in carboy lots, is commonly used. One 
pound of acid is sufficient for fifteen tests. The acid 
should be kept in stoppered glass bottles, preferably 
glass or rubber stoppered ones, since a cork stopper is 
soon dissolved by the acid and rendered useless. If the 
bottle is left uncorked the acid will absorb moisture from 
the air and will after a time become too weak for use in 
this test. Lead is the only common metal which is not 
dissolved by strong sulfuric acidj where considerable 
milk testing is done, it is therefore desirable to provide 
a table covered with sheet lead on which the acid may 
be handled. 



1 A specific gravity of 1.82 means that a given volume of the acid weighs 
1.82 times as much as the same volume of water at the same temperature 
(see also under Lactometer, 106) 



64 Testing Milk and Its Products, 

The acid dissolves iron, tin, wood and cloth, and burns 
the skin. If acid is accidently spilled, plenty of water 
should be used at once to wash it off. Ashes, potash, 
soda, and ammonia neutralize the action of the acid, and 
a weak solution of any one of these alkalies can be used 
after the acid has been washed off with water. The red 
color caused by the action of the acid on clothing can be 
removed by wetting the spot with weak ammonia water; 
the ammonia must, however, be applied while the stain 
is fresh, and is in its turn washed off with water. 

73. Testing the strength of the acid. The strength of 
the acid can be easily tested by the use of such a balance 
as shown in fig. 34 (91). A dry test bottle is weighed, 
and then filled with acid exactly to the zero mark, or to 
any other particular line of the scale. It is then again 
weighed accurately; the difference between these two 
weights will give the weight of the acid in the bottle. 
l!^ext empty the bottle and rinse it thoroughly with water 
(until the water has no longer an acid taste); fill the 
bottle with water to the same line as before and weigh; 
the difference between this weight and that of the empty 
bottle gives the weight of the same volume of water as 
that of the acid weighed. Divide the weight of the acid 
by the weight of the water; the quotient gives the spe- 
cific gravity of the acid. If this is between 1.82 and 
1.83, the strength of the acid is correct. The outside of 
the test bottle should always be wiped dry before the 
liquids are weighed in it. Unless great care is taken in 
measuring out the acid and the water, and in weighing 
both these and the test bottle, the results obtained will 
not be trustworthy. 



The BabcocTc Test 65 

74. Too strong acid can sometimes be successfully used 
by taking less than the required amount of each test, e. g., 
about 15 cc. Operators are warned against reducing the 
strength of the acid by adding water to it, as accidents 
are very apt to occur when this is done. A too strong 
acid can, if desired, be weakened by simply leaving the 
bottle uncorked for a time, or by pouring the acid into a 
bottle containing a small quantity of water. In the lat- 
ter case the first portions of acid should be added care- 
fully, a little at a time, shaking the bottle after each 
addition, so as not to cause it to break from the great 
heat evolved in mixing the acid and the water. Never 
dilute sulfuric acid by pouring water into it. 

75. If the acid is too weak, correct results may some- 
times be obtained by using more than the specified 
quantity, say 20 cc. If a good test is not obtained with 
this quantity of acid, a new lot must be secured, as its 
specific gravity in such a case is below 1.82. The ob- 
serving operator will soon be able to judge' of the 
strength of the acid by its action on milk in mixing the 
two liquids in th6 Babcock test bottles; it is indeed re- 
markable what slight differences in the specific gravity 
of the acid will make themselves apparent in working 
the test; as regards the rapidity with which both the 
curdled milk is dissolved and the mixture of acid -and 
milk turns black. 

76. Strength of sulfuric acid. The relation between 
the strength of sulfuric acid and its specific gravity will 
be seen from the following table : 



66 Testing Milk and Its Products. 

Strength of Sulfuric Acid {Lunge and Isler,1890.) 

Sulfuric Acid Specific Gravity 

iH^SO^). {15° C, water U°C). 

97 per cent 1.841 

96 " .......1.840 

95 " 1.839 

94 " 1.837 

93 " : 1.834 

92 " 1.830 

91 " V 1.825 

90 " 1.820 

89 '' 1.815 

88 " 1.808 

It will be noticed tbat the sulfuric acid to be used in 

the Babcock test should contain 90 to 92 per cent, of acid 

(H2SO4); slightly weaker or stronger acid than this may, 

as previously stated, be used by adjusting the quantity 

of acid taken for each test to the strength of the acid, but 

successful tests cannot be made with acid weaker than 

89 per cent, or stronger than 95 per cent. 

77. The Swedish acid tester is a small hydrometer, intended to 
show whether the acid to be used in the Babcock test is of the 
correct strength. We have examined a number of these testers, 
and have found them practically useless for the purpose in- 
tended. The reason for this is that the instrument is not suflfl- 
ciently sensitive; while the testers examined were found to sink 
to the line marked Correct on the scale, when lowered into sul- 
furic acid of a specific gravity of 1.83, they would sink to a point 
much nearer the same mark, than to the lines marked Too 
strong or Too lueak^ respectively, when lowered into either too 
strong or too weak acid. 

78. The color of the fat column an index to the strength 
of the acid used. The strength of the acid is indicated 
to a certain extent by the color of the fat which separates 
in the neck of the test bottle when milk is tested. If the 
directions given for making the tests are carefully fol- 
lowed, the fat separated out will be of a golden yellow 



ThelBabcock Test. 67 

color. If the fat is light colored or whitish, it generally 
indicates that the acid is too weak, and a dark colored 
fat, with a layer of black material beneath it, shows that 
the acid is too strong, provided the temperature of both 
milk and acid is about 70°. [For influence of tempera- 
ture, see next paragraph.] 

The strength of the acid used in the test is not suf- 
ficient at ordinary temperatures of testing to appreciably 
dissolve the fat, but a variation in the strength of the 
acid or in the temperature of the milk influences the 
intensity of the action of the acid on the fat, as shown in 
the color of the fat obtained. 

The following experiment shows the relation between 
the strength of the acid, the temperature of the milk, 
and the color of the fat: 

First:— Yvova a sample of milk measure the usual quantity 
for testing into each of three bottles, A, B and C. Place A in 
ice water, and C in warm water, having bottle B at the ordi- 
nary temperature. After the bottles have been left for ten min- 
utes under these conditions, add the normal quantity of acid 
to each and proceed with the test in the ordinary manner. 

Second; — Measure some of the same milk into three other 
bottles, D, E and F. Into test bottle D pour the usual amount 
of rather weak acid; add the same amount of acid of normal 
strength (1.82-1.88) to bottle E, and add 17.5 cc. of a still 
stronger acid (concentrated sulfuric acid, sp. gr. 1.84), in test 
bottle F; complete these tests in the usual way. 

On the completion of the preceding six tests the operator will 
notice that the fat in the necks of test bottles A {cold milk) and 
D {weak acid) is much lighter colored than that in C {warm 
milk) and F {strong acid), and that the color of the fat in B 
{normal temperature) and E {normal acid) is somewhere be- 
tween that of these two series. 

79. Influence of temperature on the separation of fat. 

The intensity of the action of the sulfuric acid on the 



68 Testing Milk and Its Products. 

milk is influenced by the temperature of either liquid ; 
the higher the temperature, the more intense will be the 
action of the acid on the solids of the milk. It may be 
noticed that acid from the same carboy will act differently 
on milk in summer than in winter time, if the acid and 
the milk are not brought to a temperature of about 70° 
before testing during both seasons. The temperature of 
the liquids may be as low as 40° F. in winter and as high 
as 80° F. in summer. This difference of forty degrees 
will often have considerable influence on the clearness of 
the fat separated, showing white curdy substances and a 
light colored fat in winter, or black flocculent specks, 
with a dark colored column of fat in summer. Both these 
defects can be avoided when the acid is of the proper 
strength, by bringing the temperature of the milk and 
the acid to about 70° F. before the milk is tested. 

The operator should be particularly cautious against 
over-heating either milk or acid; so intense an action 
may be caused thereby as to force the hot acid out of the 
neck of the test bottle when it is added to the milk, thus 
spoiling the test and possibly causing an accident. 

4. — Water to be used in the Babcock Test. 

80. Rain water, condensed steam, or soft water should 
be used for the purpose of bringing the fat into the neck 
of the test bottles. The surface of the fat column will 
then usually be clear and distinct. The foam or bubbles 
that sometimes obscure the upper line (meniscus) of the 
fat, making indistinct the point from which to measure 
it, is generally caused by the action of the acid on the 
carbonates in hard water. The carbonic acid gas liber- 



The Bdbcock Test. 69 

ated from hard water by the sulfuric acid is more or less 
held by the viscid fat aud produces a layer of foam on 
its surface. If clean soft water cannot be obtained for 
this purpose, hard water may be used by adding a few 
drops of sulfuric acid to the water before it is heated, 
thus causing the carbonic acid to be driven out of it. 
By simply boiling, many hard waters will be rendered 
soft and adapted to use in the Babcock test, as most of 
the carbonates which cause this foaming are thereby 
precipitated. 

If the test has been completed, and a layer of foam ap- 
pears over the fat, it may be destroyed by adding a drop 
or two of alcohol. If this is done, the fat column should 
be read at once after the alcohol is added, as the latter 
will soon unite with the fat and increase its volume. 

81. Reservoir for water. When only a few tests are 
made at one time, the hot water can be added with the 
17.6 cc. pipette. If many tests are made, the water is 
more conveniently and quickly filled into the test bottles 
by drawing it from a small copper reservoir or tin pail 
suspended over the testing machine.^ The flow of 
water through a rubber tube connected with the reser- 
voir, is regulated by means of a pinch cock. The 
water must be hot when added to the test bottles so as to 
keep the fat in a melted condition until the readings are 
taken. Most turbine testers are now made with a 
very convenient water reservoir attached to the tester 
(figs. 23-25). 



1 Ordinary tinware rusts very soon when water is left standing in it, 
and copper reservoirs are ttierefore more economical. 



70 



Testing Milk and Its Products. 



The use of zinc or steel oilers, or perfection oil cans 
has been suggested, as a handy and rapid method of 
adding hot water to the test bottles. 

5. — Modifications or the Babcock Test. 

82. The Russian milk test. The same chemical and 
mechanical principles applied in the regular Babcock 




=■2 
|-o 

1-2 
|-3 

|-S 

§■7, 



Fig. 26. The Russian test. 

test, are used in the Russian milk test, except 
that in this case the machine in which the 
bottles are whirled, and the bottles them- 
selves, are so constructed that the latter can 
be filled with hot water while the machine is 
running at full speed, thus saving time and 
trouble incident to the stopping of the tester 
and filling the bottles by means of a pipette. Test bottle 
The milk- measuring pipette (fig. 28) and the Russiantest. 
acid measure used in the Russian test are one-half of the 
ordinary size, and the test bottles are made in two pieces, 
with a detachable narrow graduated stem (see fig. 27). 
The machine is substantially made of cast iron 5 it is pro- 



The Babcock Test 



71 



H 



vided with a very satisfactory speed indicator which 
shows at any time the number of revolutions at which 
the bottles are being turned. The accompanying illus- 
trations show the apparatus used in the Eus- 
sian test. When the directions for operating 
the test are followed closely, the results ob- 
tained are accurate aud very satisfactory. 

83. Bartlett's modification. Bartlett^ pro- 
posed a modification of the method of pro- 
cedure in the Babcock test, which aims to 
simplify the manipulations. 20 cc. of acid 
are added, instead of 17.5 cc, and the bottles 
filled with the milk-acid mixture are left 
standing for not less than five minutes and 
then filled with hot water to within the scale; 
the bottles are then whirled for five minutes 
at the regular rate (52). 

In the experience of the authors the modi- 
hi^th?]Rui fication can not always be depended upon to 
sian test. ^-^^ satisfactory results. When published it 
was tried by each of the one hundred students in the 
Wisconsin Dairy School 5 while some of these operators 
obtained a clear separation of fat, and results that com- 
pared favorably with those made by the regular Babcock 
test, others failed to obtain correct results with the 
method as modified. It is not known that the modifica- 
tion has proved superior to or taken the place of the 
regular Babcock test to any extent.^ 



1 Maine experiment station, Bull. No. 31 (S S.). 

2 The German dairy chemist Siegfeld in 1899 proposed a modification of the 
Babcock test( Molkerei Ztg., Hildesheim, 1899, p. 51) using 2 cc. of amy 1 alcohol 
with the sulfuric acid, and filling upwithdilutesulfuricacid(l:l, sp.gr. 1.5) 



72 



Testing Milk and Its Products. 



84. Bausch and Lomb centrifuge. Fig. 29 shows a 
form of hand centrifuge which may be used to advantage 
by physicians or in a pathological laboratories for the 
determination of fat in milk. The centrifuge is espe- 
cially designed for examination of urine, sputum, blood, 
etc., but has been adapted to milk analysis by the Leff- 

mann & Beam test, a special 
form of bottle (fig. 30) having 
been constructed for this pur- 
pose. The machine gives sat- 
isfactory results by the Bab- 
cock test as well, provided 
the acid used is 1.83-1.84, or 
if the bottles containing the 
acid-milk mixture 
be placed in hot 
water for five or ten 
minutes prior to 
the whirling. As 
the bottles are cali- 
brated for only 5 





Fig. 29. Physician's centrifuge 
that may be used for milk testing 



Fig. 30. Test 

bottle for cc. of milk and the 

physician's 

centrifuge, j^eck of the bottles, 



with scale, is correspoLdingly fine, testing milk with this 
machine requires some nicety of manipulation not called 
for in case of testers constructed for the use of farmers 
and dairymen. 

in one filling, in place of water after the whirling. Aclear separation of the 
fat is facilitated by both these changes, but when properly conducted there 
is no difficulty whatever in obtaining a clear fat column in the Babcock test 
as described in this book, and the modification will not therefore be likely 
to be introduced in American factories. It has become quite generally 
adopted in North German creameries where the Babcock test isused. 



CHAPTER lY. 
CREAn TESTING. 

85. Cream may be tested by the Babcock test in the 
same manner as milk, and the results obtained are accu- 
rate when the necessary care has been taken in sampling 
the cream and measuring the fat. The composition of 
cream varies greatly according to the process of cream- 
ing, temperature of milk during the creaming, quality 




Fig. 31. 
Students testing (^airy products, 



and composition of the milk to be creamed, etc. The 
cream usually met with in separator creameries will con- 
tain from 25 to 50 per cent., or on the average about 35 
per'cent. of fat. Cream from hand separators may be as 



74 Testing Milk and Its Products. 

rich as this, but as delivered to creameries it often con- 
tains only 20 per cent, of fat. An average grade of market 
cream as retailed contains about 25 per cent, of fat. If 18 
grams of 25 per cent, cream is measured into an ordinary 
Babcock test bottle, there will be 18 X. 25 =4. 5 grams 
(or, since the specific gravity of butter fat is about .9, 
^ = 5 cc. ) of pure butter fat in the bottle. It is shown, 
however, (p. 38), that the space from to 10 in the neck 
of these bottles holds exactly 2 cc. The neck of the milk 
test bottles will not be large enough to show the per cent, 
of fat in a sample of cream if 18 gratns are taken for test- 
ing, and it is therefore necessary to adopt special meas- 
ures when cream is to be tested. 

86. Errors of measuring cream. Several factors tend 
to render inaccurate the measuring of cream for the Bab- 
cock test, and correct results can therefore only be ob- 
tained by weighing the cream. If a 17.6 cc. pipette is 
used for measuring the cream, it will not deliver 18 
grams of cream, as it will of milk, for the following 
reasons: 

1. The specific gravity of cream is lower than that of 
milk; if a certain quantity of milk weighs 1030 lbs., the 
same quantity of cream will weigh from 1020 lbs. to be- 
low 1000 lbs., the weight being determined by the rich- 
ness of the cream; the more fat the cream contains, the 
less a certain quantity of it, e. g., a gallon will weigh. ^ 

2. Cream is thicker (more viscous) than milk at the 
same temperatures, and more of it will adhere to the sides 
of the measuring pipette than in case of milk. This is of 
special importance in testing very rich or sour cream. 

1 For specific gravity of cream of different richness, see table on p,75. 



Cream Testing. 75 

3. In case of separator cream, more or less air will 
become incorporated with the cream during the process 
of separation. In the ripening of cream, the fermenta- 
tion gases developed are held in the cream in the same 
way as bread dough holds the gases generated by yeast. 
In either case the weight of a certain measure of cream 
is diminished. 

87. As an illustration of the effect of the preceding 
factors on the amount of cream measured out by a Bab- 
cock 17.6 cc. pipette, the following weighings of separ- 
ator cream are given (column &). The cream was in 
all cases fresh from the separator 5 it was weighed as de- 
livered by the pipette into a cream test bottle (91), and 
the test proceeded with at once; the specific gravity of 
the cream was determined by means of a picnometer, 
(247). The data given are in all cases averages of sev- 
eral determinations: the samples of cream have been 
grouped according to their average fat contents.^ 
Weiqlit 0/ fresh separator cream delivered hy a 17.6 cc. pipette. 



Per cent 
of fat in 


Specific gravity {17 5° C.) 




Weight of Cream deliv- 
ered, grams. 


cream. 


(a) 








(&) 


10 


1.023 








17.9 


15 


1.012 








17.7 


20 


1.008 








17.3 


25 


1.002 








17.2 


30 


.996 








17.0 


35 


.930 








16.4 


40 


.966 








16.3 


45 


.950 








16.2 


50 


.947 








15.8 


The figures 


in the table 


show 


plainly 


the variations 


in the specific gravity of cream of different richness and 



1 For influence of condition of cream on the amount measured out with 
a 17.6 cc. pipette, see also Bartlett, Maine exp, sta., Bull. 31 (S. S. ), 



76 Testing Milk and Its Products. 

the error of making tests of cream by measuring it with 
a 17.6 cc. pipette, especially if the pipette is not rinsed 
and the washings added to the test bottle; if the cream 
to be sampled is fresh separator cream testing over 30 
per cent, less than 17.0 grams of cream will be delivered 
into the test bottle, and the results of the reading will 
be at least one-eighteenth too low, or about 1.4 per cent, 
on a 25 per cent, cream. If the creiam is sour, the error 
will of course be still greater. 

It should be remembered that the specific gravities of 
the cream given in the table refer to fresh separator 
cream only. Considerable air is incorporated during the 
separation, and cream of this kind is therefore lighter 
than gravity cream of corresponding fat contents. 

88. Weighing cream for testing. For the reasons stated 
in the preceding, accurate tests of cream can only be 
made by weighing the cream into the Babcock test bottles. 
This is recognized by a law passed by the Wisconsin leg- 
islature of 1903, which requires cream to be weighed for 
testing where it is sold on the basis of its fat content. ^ 

The simplest method is to weigh 9 or 18 grams of the 
sample on a small cream weighing scale (seep. 79) into 
one of the special forms of cream-test bottles. 

Cream test bottles. Special forms of bottles have 
been devised for testing samples of cream by the Bab- 
cock test by Bartlett of Maine, Winton of Connecticut, 
and by various manufacturers. 
' 89. The bulb-necked cream bottles (fig. 32) allow the 



1 Chapter 43, laws of 1903, An act to prescribe the standard measures for 
the use of the Babcock test in determining the per cent, of butter fat in 
milk or cream. 



Cream Testing. 



11 



testing of cream containing 23 or 25 per cent, of fat, 
when the usual quantity of cream (18 grams) is taken. 
The neck is graduated from to 23 per cent., 
and in some cases to 25 per cent. , the gradua- 
tion extending both below and above the bulb. 
This is sometimes an inconvenience, as the 
water must be added carefully so that the 
lower end of the column of fat will always 
come below the bulb, in the graduated part of 
the neck, and not in the bulb itself. Espec- 
ially in case of beginners, tests are often lost 
when this bottle is first used, for the reason 
given. It is recommended to fill these bottles 
with the first portion of hot water to just above 
the bulb, so that one can see how much water 
to add the second time in order to bring the 
fat within the scale. 

Each division of the scale on these cream 
bottles represents two-tenths of one per cent, of 



1: 



fat, as in case of the milk test bottles. This buib-necked 
form of bottle is no longer used to any extent, bottle. 
as it has been largely replaced by the cream-bottle de- 
scribed in the following paragraph. 

90. The >\inton cream bottle. The cream test bottle 
devised by Winton,^ (fig. 33), has a neck of the usual 
length, and of sufficient width to measure 30 per cent, of 
fat. The scale of the neck is divided into one-half per 
cents., but readings of a quarter of a per cent, can easily 
be estimated. Determinations of fat in cream accurate 



1 Connecticut experiment station (New Haven), Bull. No. 117; report 
1894, p. 224. 



78 



Testing Milk and Its Products. 






en 



to a quarter of a per cent, are sufficiently exact for most 
commercial purposes, e. g., in 
creameries, and this form of cream 
bottle will be found very convenient 
in making tests of composite sam- 
ples of cream. 

Cream test bottles of a smaller 
bore, similar to that shown in fig. 
33, are greatly to be preferred to 
those with wide necks, since they 
permit of accurate readings to a 
quarter of a per cent. 

Other forms of cream- test bottles 
which will allow the testing of 50-55 
per cent, cream have been placed 
on the market during late years 
by some manufacturers. These bot- 
tles have very long necks and re- 
quire especially constructed, large 
and deep (and therefore costly) 
testers (see fig. 25). It does not ap- 
pear that these machines or accom- 
panyingbottleshave met with gener- 
al favor among creamery operators. 
91. Scales for weighing the cream. 
When a small, delicate balance is 
used, cream can be weighed rapidly 
into the bottles. Either of the scales 
shown in the accompanying illustra- 
tions (fig. 34-35), will be found 
sufficiently accurate for this pur- 
pose; a small scale of this kind is also convenient and 



=:30 

E;26 
|-24 

E;22 

9-20 
^18 
=-16 
^14 
E^12 

E- 8 
£4 

— o' 



Fig. 33. The cream 
test bottle. 



Cream Tc sting. 79 

helpful in testing cheese, butter and condensed milk, 
in determining the strength of sulfuric acid, and the 
accuracy of test bottles and pipettes (q. v.). In 
testing cream by weight, the test bottle is first 
weighed empty, and again when 9 or 18 grams of 
cream have been placed in it; the difference between the 
two weights gives the weight of cream taken for the test. 
If the cream contains less than 30 per cent, of fat, the 
regular milk test bottle can be used for testing the 
cream, if not much more than 5 grams are weighed out; 




Fig. 3i and 35. Scales used for weighing cream, cheese, etc., in the 
Babcock test. 

if more cream is taken, or if this is richer than 30 per 
cent. , it is advisable to use the cream bottle. 

The cream scale shown in fig. 35 permits the weighing 
of six samples of cream on each pan with only one taring 
of the bottles, which greatly facilitates the work of test- 
ing the cream. 

The operator should be careful in weighing the cream 
not to spill it on the outside of the test bottle. If less 
than 18 grams of cream has been weighed into the bottle, 
sufficient water is added to the bottle to make the total 
volume about 18 cc. The usual quantity of acid (17.5 cc. ) 
is then added, and the test completed in the ordinary 
manner.. The reading of the amount of fat in the neck 
of the test bottle will not show the correct per cent, of 



80 Testing Milk and Its Products. 

fat in the cream, unless 18 grams were weighed out. If 
less than 18 grams were taken the per cent, of fat in the 
cream tested is obtained by multiplying the reading by 
18, and dividing the product by the weight of the cream 
taken. 

Example: Weight of cream tested, 5. 2 grams; reading of col- 
umQ of fat ^'9.8, 2)9.7, average 9.75; percent, of fat in the cream 
9.75X18 



5.2 



:33.75. 



It is very convenient to weigh out 18 grams of cream 
(or a fraction thereof) so that the readings may be taken 
directly from the neck of the bottle. The smaller the 
quantity of cream taken for a sample, the greater is 
the error introduced by inaccurate weighings or read- 
ings. The reading is rendered more accurate and cer- 
tain if a number of tests of a sample are made, at least 
two or three, and the results averaged. 

92. Measuring cream for testing. Where a special 
cream scale or a small balance is not available, fairly 
satisfactory results may be obtained with cream of 
low or average quality by measuring out the sam- 
ple with a 17.6 pipette and correcting the results as 
indicated below. One of the cream testbottles or a 
common milk test bottle may be used for this purpose. The 
table given on p. 75 shows that a 17.6 cc. pipette, 
in the case of cream containing less than 25 per cent, 
fat and fresh from the separator, will deliver only 
17.2 grams of cream, that is, the results will be Vg^ or 
. 44 per cent, too low. In the same way in case of 40 
per cent, cream only 16.3 grams of cream would be de- 
livered, and the results therefore .94 per cent, too 



Cream Testing. 81 

low. When the cream has been ripened or is thick, 
less cream woald be delivered than the amounts 
given, and the error introduced by measuring out 
the samples correspondingly increased. A table of 
correction for testing such cream by measuring the sam- 
ple has been prepared by Prof. Eckles of Iowa experi- 
ment station.^ 

Approximately correct results may be obtained in 
testing thin cream by using an 18 cc. measuring pipette; 
to avoid the expense and trouble of using two different 
pipettes, one for milk and one for cream, a pipette with 
two marks on the stem, at 17.6 cc. and 18 cc, has been 
placed on the market, the former mark being used when 
milk is tested, and the latter for cream. ^ 

93. Use of milk test bottles. Cream may be tested by 
emptying a 17.6 cc. pipetteful of the sample into two or 
more milk test bottles, dividing the amount about equally 
between the bottles and filling the pipette with water once 
or twice, which is then in turn divided about equally 
between the test bottles; the per cent, of fat in the cream 
is found by adding the readings obtained in each of the 
bottles. Milk and water must be mixed he/ore the acid 
is added. 

This method does away with the error incident to the 
adhesion of cream to the side of the pipette, but not that 
due to the low specific gravity of the cream, and the re- 
sults obtained will therefore be too low. The dilution of 



1 Press Bull, dated August, 1901. 

2 Professor Spill man, in Bull. 32 of Washington experiment station, 
recommends the use of a 17 6 cc. pipette for testing cream, the results ob- 
tained being corrected by a certain per cent., as shown in a table given in 
the bulletin. The table is based on the flgures given on p. 74 of this book, 
and is therefore only applicable to fresh separator cream. 



82 Testing Milk and Its Products. 

the cream with water in the test bottles not only makes 
it possible to bring into the bottle all the cream measured 
out, but also insures a clear test. If ordinary cream is 
mixed with the ordinary quantity of sulfuric acid used in 
the Babcock test, a dark- colored fat will generally be 
obtained, while the cream diluted with an equal or twice 
its volume of water, when mixed with the ordinary amount 
of acid, will give a light yellow, clear column of fat, which 
will allow of a very distinct and sharp reading. 

The number of bottles to be used for testing a sample 
of cream by this method must be regulated by the rich- 
ness of the cream. If the sample probably contains 20 
per cent, or more, a pipetteful should be divided nearly 
equally between three milk test bottles, and two-thirds 
of a pipetteful of water is added to each bottle. If the 
cream contains less than 20 per cent, of fat, it will only 
be necessary to use two milk test bottles, dividing the 
pipetteful between these, and adding one half of a pipette- 
ful of water to each bottle. 

By using cream test bottles (90), more accurate tests 
may be obtained in case of cream containing as much as 
25 per cent, of fat, by dividing one pipetteful between 
two bottles, rinsing half a pipette of water into each one, 
than by adding all the cream to one bottle without rins- 
ing the pipette, for reasons apparent from what has been 
said in the preceding. 

94. Ise of a 5 cc. pipette When the cream is in good 
condition for sampling, satisfactory results can be ob- 
tained by the use of a 5 cc. pipette, provided great care 
is taken in mixing the cream before sampling; 5 cc. of 
cream are measured into a milk test bottle, and two 



Cream Testing. 



83 



pipettefuls of water are added. In this way all tlie cream 
in the pipette is easily rinsed into the test bottle. The 
readings multiplied by ^^=S.Q will give the per cent, of 
fat in the cream. If the specific gravity of the cream 
tested varies appreciably from 1, corrections should be 
made accordingly J e. g., if the specific gravity is 1.02; 



the factor should read 



3.53; if. 95, 



18 
5x95" 



3.79, etc. 



■d 



95. Proper readings of cream tests. The accompanying 
illustration (fig. 36), shows the proper method of read- 
ing the fat column in cream tests; read- 
ings are taken from a to &, not to d or to c. ^ 
No special precautiors other than 
those required in testing milk have been 
found necessary in testing cream, ex- 
cept that it is sometimes advisable not 
to whirl the test bottles in the cen- 
trifuge at once after mixing, but to let 
the cream-acid mixture stand for a while, 
until it turns dark colored. At first, 
the mixture of cream and acid is much 
lighter colored than that of milk and 
acid, owing to the smaller amount of 
solids not fat contained in the cream. 
Fig 86. Measur- ^^^ liquid beneath the fat in a com- 
m^the^ n^cr^Sf^a pletcd tcst of cream IS sometimes m ilky and 
i'ng^s'houid be inade the fat appears whitc and cloudy, making 
or toe. ' an exact reading difficult. Such defects 

can usually be overcome by placing the test bottles in hot 
water for about ten minutes previous to the whirling, or 




1 The size of the meniscus is magnified in the cut. 



84 Testing Milk and Its Products. 

by allowing the fat to crystalize (which is done by cool- 
ing the bottles in cold water after the last whirling) and 
remelting it by placing the bottles in hot water. 

96. The error due to the expansion of the fat in case 
of excessively hot turbine testers having no openings in 
the cover as mentioned on p. 36, is especially noticeable 
in cream testing, where it may amount to one per cent, 
or more. In order to obtain correct results with such 
testers, the hot cream test bottles must be placed in 
water at about 140° F. for a few minutes before the 
results are read off. 



CHAPTER V. 
BABCOCK TEST FOR OTHER MILK PRODUCTS. 

97. Skim milk. Each division on the scale of the neck 
of the regular Babcock test bottle represents two- tenths of 
one per cent. (44). When a sample of skim milk or butter 
milk containing less than this per cent, of fat is tested, the 
estimated amount is expressed by different operators as 
one-tenth, a trace, one-tenth trace, or one to five- 
hundredths of one per cent. Gravimetric chemical 
analyses of skim milk have shown that samples which 
give only a few small drops of fat floating on the water 
in the neck of the test bottle, or adhering to the side of 
the neck, generally contain one- tenth of one per cent, of 
fat, and often more. Samples of skim milk containing 
less than one-tenth of one per cent, of fat are very rare, 
and it is doubtful whether a sample of separator skim 
milk representing a full run of, say 5,000 lbs. of milk, has 
ever shown less than five-hundredths of one per cent, of 
fat. Under ordinary factory conditions, few separators 
will deliver skim milk containing under one-tenth of one 
per cent, of fat, when the sample is taken from the whole 
day's run. This must be considered a most satisfactory 
separation. ^ 

98, The reason why the Babcock test fails to show all 
the fat present in skim milk must be sought in one or 
two causes: a trace of fat may be dissolved in the sulfuric 
acid, or owing to the minuteness of the fat globules of 

1 For comparative analyses of separator skim milk by the gravimetric 
method and by the Babcock test, see Wis. exp. station bull. 52 and rep. 
XVII, p. 81; see also Woll, Testing skim milk by Babcock test, in Country 
Gentleman, April 26, 1902. 



86 Testing Milk and Its Products. 

such milk they may not be brought together in the neck 
of the bottles at the speed used with the Babcock test. ' 
The latter cause is the more likely explanation. If a drop 
of the dark liquid obtained in a Babcock bottle from a 
test of whole milk, be placed on a slide under the micro- 
scope, it will be seen that a fair number of very minute 
fat globules are found in the liquid. These globules are 
not brought into the column of fat in the neck of the bottle 
by the centrifugal force e'xerted in the Babcock test, unless 
the bottles are whirled in a turbine tester in which they 
are heated to 200° F. or higher, (see 71) ; the loss of the fat 
contained in these fine globules is compensated for, in the 
testing of whole milk, by a liberal reading of the column 
of fat separated out, the reading being taken from the 
lower meniscus of the fat to the top of the upper one (see 
p. 35) ; in some separator skim milk, on the other hand, not 
enough fat remains to completely fill the neck, and the ap- 
parent result of the reading must therefore be increased 
by from five-hundredths to one-tenth of one per cent. 

It follows from what has been said that tests of skim 
milk showing no fat in the neck of the test bottles on 
completion of the test, generally indicate inefficient work 
of the centrifugal tester or of the operator, or of both. 
The test should be repeated in such cases, using more acid 
and whirling for full five minutes. Separator skim milk 
should be allowed to stand 10 to 15 minutes for the air 
to escape before the sample is taken. 

In order to bring as much fat as possible into the neck 
of the bottles in testing skim milk, it is advisable to add 
somewhat more acid than when whole milk is tested, viz., 
about 20 cc, and to whirl the bottles at full speed for at 



Bahcock -Test for other Milk Products, 



87 



least five minutes, keeping the tester as hot as possible 
the whole time.^ The readings must be taken as soon as 
the whirling is completed, as owing to the contraction 
of the liquid by cooling, the fat otherwise 
adheres to the inside of the neck of the test 
bottle as a film of grease which cannot be 
measured by the scale. 

99. The double-necked test bottle, (fig. 
37), suggested by one of us, ^ is made espe- 
cially for measuring small quantities of fat 
and gives most satisfactory results in testing 
skim milk and butter milk. Each division 
of the scale in these bottles represents five- 
hundredths of one per cent., and the marks 
are so far apart that the small fat column 
can be easily estimated to single hundredths 
of one per cent. In the first forms, now 
out of use, the neck was graduated to hun- 
dredths of one per cent. 

The value of the divisions of the scale on 
the double- necked test bottles has been a 
subject of considerable discussion, and vari- 
ous opinions have been expressed whether 
they show one-tenth or one- twentieth (.05) 
of one per cent, of fat. By calibration with mercury the 
value of the divisions will be found to be . 05 or one- 
twentieth of one per cent., but as shown above, the 
results obtained in using the bottles for thin separator 
skim milk often come at least .05 per cent, too low, so 
that, practically speaking, each division may be taken to 



Fig. 37. The 
double-neck ed 
skim milk bot- 
tle (sometimes 
(ailed the Ohl- 
son or B. & W. 
bottle ) 



1 See Wis. exp. station, report XVII, p. 81. 

2 Farrington, and first constructed by Mr. J . J. Nussbaumer, of Illinois 



88 



Testing Milk and Its Products. 



show one tenth of one per cent., if the fat fills only one 
division of the scale or less.^ 

The double- necked bottle is very convenient for the 
testing of separator skim milk, thin butter milk and 
whey. The milk, acid and water are added to the bottle 
through the large side- tube; the raixing of milk and acid 
must be done with great care, so that none of the con- 
tents is forced into the fine measuring tube and lost; it is 
best to add half of the acid first and mix it with the milk, 
and then add the rest. When the fat is 
in the lower end of the measuring tube, 
it can be forced into the scale by pressing 
with the finger on the top of the side tube. 
In placing the double necked bottle in 
the tester they should be put with the 
filling tube toward the center so as to 
avoid any of the fat being caught be- 
tween this tube and the side of the bot- 
tle when it resumes a vertical position. 
This test bottle is more fragile and ex- 
pensive than the ordinary Babcock bot- 
tles, and must be carefully handled; it 
has recently been made of heavier glass 
and this form is to be highly recom- 




FiG. 38. The Waguer 

skim milk bottle, mended . ^ 



100. The double-sized skim milk bottle is of no particular 
value. It is difficult to obtain a thorough mixture of 



1 Wis. experiment station, bull. 52; Penna. experiment station, report 
1896, p. 221. 

2 A copper double-necked test bottle with a detachable graduated glass 
neck was designed and tried by one of us (F.) a few years ago, but no 
special advantages over the glass bottle was found for it. 



Babcock Test for other Milk Products. 89 

the milk and the acid in these bottles, and the tests 
invariably come too low, more so than with the regular 
Babcock bottles or the double-necked skim milk bottles, 
for reasons that are readily seen. 

101. Buttermilk and whey. The testing of buttermilk or 
lohey by the Babcock test offers no special difficulties, and 
what has been said in regard to tests of separator skim 
milk is equally true in case of these by-products. Whey 
contains only a small quantity of solids not fat, viz., less 
than 7 per cent. (27), and the mixing with acid and the 
solution of the whey solids therein is therefore readily 
accomplished; the acid solution is of a light reddish color, 
turning black but very slowly. 

102. Cheese. Cheese can be easily tested by the Bab- 
cock test if a small scale (fig. 34) is at hand for weighing 
the sample; the results obtained will furnish accurate 
information as to the amount of fat in the cheese, provided 
good judgment and exactness are used in sampling and 
weighing the cheese. The following method of sampling 
cheese is recommended: ^ 

'^ Where the cheese can be cut, a narrow wedge reach- 
ing from the edge to the center of the cheese will more 
nearly represent the average composition of the Cheese 
than any other sample. This may be cut quite fine, with 
care to avoid evaporation of water, and the portion for 
analysis taken from the mixed mass. When the sample 
is taken with a cheese trier, a plug taken perpendicular 
to the surface, one-third of the distance from the edge to 
the center of the cheese, will more nearly represent the 
average composition than any other. The plug should 

1 U. S. Dept. of Agriculture, Chenaical Divison, bull. No. 46, p. 37. 



90 Testing Milk and Its Products. 

either reach entirely through or only half way through 
the cheese. 

" For inspection purposes the rind may be rejected, but 
for investigations, where the absolute quantity of fat in 
the cheese is required, the rind should be included in the 
sample. It is well, when admissible, to take two or three 
plugs on different sides of the cheese and after splitting 
them lengthwise with a sharp knife, take portions of each 
for the test." 

103. When a satisfactory sample of the cheese has been 
obtained, about 5 grams are weighed into a milk test 
bottle, or a larger quantity may be used with a cream 
test bottle. The test bottle is first weighed empty, and 
again after the pieces of cheese have been added. About 
15 cc. of warm water is added to the cheese in the test 
bottle, and this is shaken occasionally until the cheese 
softens and forms a creamy emulsion with the water. 
A few cc. of acid will aid in this mixing and disintegra- 
tion, the process being hastened by placing the bottles 
in tepid water. When all lumps of cheese have disap- 
peared in the liquid, the full amount of acid is added, 
and the test completed in the ordinary manner. 

The per cent, of fat in the cheese is obtained by multi- 
plying the reading of the fat column by 18 and dividing 
the product by the weight of cheese added to the test 
bottle. The weighing of the cheese and the reading of 
the fat must be done with great care, since any error 
introduced is more than trebled in calculating the per 
cent, of fat in the cheese. 

104. Condensed milk. The per cent, of fat in un- 
sweetened condensed milk can be obtained by weighing 



Bdbcock Test for other Mi/Jc Products. 91 

8 grams into a test bottle and proceeding in exactly the 
same way as given under testing of cheese. It is not 
necessary to warm the condensed milk in the test bottles, 
since the solution of this in water is readily effected. 
Enough water should be added to make the total volume 
of liquid in the bottles 15 to 18 cc. 

If a scale is not available for weighing the sample, 
fairly accurate results may be obtained by dilating the 
condensed milk with water (1:3), and completing the 
test in the ordinary manner. When this is done, the re- 
sults must be corrected for the dilution which the sample 
received. 

105. Sweetened condensed milk. The testing of sweet- 
ened condensed milk presents peculiar difficulties, 
whether it is to be tested by the Babcock test or by chem- 
ical analysis. It may, however, be readily tested by the 
Babcock test by introducing certain changes in the manip- 
ulation of the test as worked out by one of us (F).^ A 
brief description of the manipulations adopted is here 
given. 

About sixty grams of condensed milk are weighed 
into a 200 cc. graduated flask, to this 100 cc. of water 
are added and the solution of the condensed milk 
effected. The flask is then filled to the mark with 
water and after mixing thoroughly, a 17.6 cc. pipette full 
is measured into a Babcock test bottle. About three cc. 
of the sulfuric acid commonly used for testing milk are 
then added and the milk and acid mixed by shaking the 
bottle vigorously. The milk is curdled by the acid, and 
make this separation complete and to compact the curd 

1 Wis. expt, stalion, report XVI r, pp. 86-89. 



92 Testing Milk and Its Products. 

the curd and whey separated somewhat. In order to 
into a firm lump, the test bottle is whirled for about six 
minutes at a rather high speed (1,000 rev.) in a steam- 
heated turbine centrifuge. 

The chamber in which the bottles are whirled ought 
to be heated to about 200° F. This can be done either 
by the turbine exhaust steam which leaks into the test- 
bottle chamber of some machines, or by means of a valve 
and pipe which will allow steam to be turned directly 
into the test bottle chamber. After this first whirling 
the test bottles are taken from the centrifuge and by be- 
ing careful not to break the lump of curd nearly all the 
whey or sugar solution can be poured out of the neck. 
Ten cc. of water are then poured into the test bottle and 
the curd is shaken up with it so as to wash out more of 
the sugar. Three cc. of acid are now added as before 
and the test bottle whirled a second time in the centri- 
fuge. The whey is decanted again and this second wash- 
ing removes so much of the sugar that what remains will 
not interfere with testing in the usual way. The curd re- 
maining in the test bottle after the second washing is 
shaken up with ten cc. of water and to this water- emul- 
sion of the curd the usual amount, 17.5 cc, of sulfuric 
acid is added and the test completed in the same way as 
milk is tested. The amount of fat finally obtained in the 
neck of the test bottle is calculated to the weight of con- 
densed milk taken. 



CHAPTEE YI. 
THE LACTOMETER AND ITS APPLICATION. 

106. The Quevenne lactometer. This instrument (see 
fig. 39, next page) consists of a hollow glass cylinder 
weighted by means of mercury or fine shot so that it will 
float in milk in an upright position, and provided with a 
narrow stem at its upper end, inside of which is found a 
graduated paper scale. In the better forms, like the Que- 
venne lactometer shown in the figure, a thermometer is 
melted into the cylinder, with its bulb at the lower end 
of the lactometer and its stem rising above the lactometer 
scale. 

The lactometer is used for the determination of the 
specific gravity of milk. The term specific gravity means 
the weight of a certain volume of a solid or a liquid sub- 
stance compared with the weight of the same volume of 
water at 4° 0. (39.2° Fahr. )5 for gases the standard of 
comparison is air or hydrogen. If the milk which a can 
will hold weighs exactly 103.2 lbs., this can will hold a 
smaller weight of water, say 100 lbs. , as milk is heavier 
than water; the specific gravity of this milk will then 
be -i^=: 1.032. 

The specific gravity of normal cows^ milk will vary in 
different samples between 1.029 and 1.035 at 60° F., the 
average being about 1.032. 

107. The lactometer enables us to determine rapidly 
the relative weight of milk and water. Its application 
rests on well-known laws of physics: When a body 
floats in a liquid, the weight of the amount of liquid 



94 



Testing Milk and Its Products. 



which, it replaces is equal to the weight 
of the body. It will siak further into a 
light liquid than into a heavy one, be- 
cause a larger volume of the former will 
be required to equal the weight of the 
body. A lactometer will therefore sink 
deeper into milk of a low specific grav- 
ity than into milk of a high specific 
gravity. 

The scale of the Quevenne lactometer 
is marked at 15 and 40, and divided into 
25 equal parts, with figures at each five 
divisions of the scale. The single divis- 
ions are called degrees. The 15 degree 
mark is placed at the point to which the 
lactometer will sink when lowered into a 
liquid of a specific gravity of 1.015, and 
the 40 degree mark at the point to which 
it will sink when placed in a liquid of a 
specific gravity of 1.040. 

The specific gravity is changed to lacto- 
meter degrees by multiplying by 1000 
and subtracting 1000 from the product. 

Example: Given, the specific gravity of a 
sample of milk, 1.0315; corresponding lacto- 
meter degree, 1 0345 X 1000-1000=34.5. 

Conversely, if the lactometer degree 
is known, the corresponding specific ^ 
gravity is found by dividing by 1000 
and adding 1 to the quotient (34.5 
= .0345; .0345 + 1 = 1.0345). 



Fig. 39. Q 

1000 lactometer 

in milk ia £ 

inder (112). 



uevenne 
floating 
, tin cyl- 



The Lactometer and Its AppUcation. 95 

108. Influence of temperature. Like most liquids, milk 
will expand on being warmed, and the same volume will, 
therefore, weigh less when warm than before; that is, 
its specific gravity will be decreased. It follows then 
that a lactometer is only correct for the temperature at 
which it is standardized. If a lactometer sinks to the 
32-mark in a sample of milk of a temperature of 60° F., 
it will only sink to, say 33, if the temperature of the 
milk is 50° F., and will sink farther down, e. g., to 31, 
if the temperature is 70° F. Lactometers on the market 
at present are generally standardized at 60° F. and to 
show the correct specific gravity the milk to be tested 
should first be warmed (or cooled, as the case may be) 
to exactly 60° F. As this is a somewhat slow process, 
tables have been constructed for correcting the results 
for errors due to differences in temperature (see Appen- 
dix, Table V). 

109. As the fat content of a sample of milk has a 
marked influence on its specific gravity at different tem- 
peratures, the CO- efficient of expansion of fat differing 
greatly from that of the milk serum, the table cannot 
give absolutely accurate corrections for all kinds of milk, 
whether rich or poor. But the errors introduced by the 
use of one table for any kind of whole milk within a 
comparatively small range of temperature, like ten de- 
grees above or below 60°, are too small to have any im- 
portance outside of exact scientific work, and in such, 
the specific gravity is always determined by means of a 
picnometer or specific gravity bottle, at the temperature 
at which this has been calibrated. In taking the spe- 
cific gravity of a sample of milk by means of a lacto- 



96 Testing MilJc and Its Products. 

meteFj the milk is always warmed or cooled so that its 
temperature does not vary ten degrees either way from 
60° F. 

no. The temperature correction table for whole milk, 
given in the Appendix shows that if, e. g., the specific 
gravity of a sample of milk taken at 68° F. was found to 
be 1.034, its specific gravity would be 1.0352 if the milk 
was cooled down to 60°. If the specific gravity given 
was found at a temperature of 51°, the corrected specific 
gravity of the milk would be 1.0329. 

In practical work in factories or at the farm, sufficiently 
accurate temperature corrections may generally be made 
by adding .1 to the lactometer reading for each degree 
above 60° F., and by subtracting .1 for each degree be- 
low 60° 5 e. g., if the reading at 64° is 29. 5, it will be about 
29.5+. 4=29.9 at 60° F. : and 34.0 at 52° F. will be 
about 34.0-. 8 = 33.2 at 60° F. The table in the Appeoi- 
dix gives 33.0 as the corrected figure in both cases. 

The scale of the thermometer in the lactometer should 
be placed above the lactometer scale so that the tempera- 
ture may be read without taking the lactometer out of 
the milk; this will give more correct results, will facil- 
itate the reading and save time. 

III. N. Y. Board of Health lactometer. In the East, and 
among city milk inspectors generally, the so called New 
York Board of Health lactometer is often used. This 
does not give the specific gravity of the milk directly, as 
is the case with the Quevenne lactometer; but the scale 
is divided into 120 equal parts, known as Board of Health 
degrees, the mark 100 being placed at the point to which 
the lactometer sinks when lowered into milk of a specific 



Oram TeMvg. 97 

gravity of 1.029 (at 60° F. ) ; this is considered the lowest 
limit for the specific gravity of normal cows' milk. The 
zero mark on the scale shows the point to which the lac- 
tometer will sink in water; the distance between these 
two marks is divided into 100 equal parts, and the scale 
is continued below the 100 mark to 120. As 100° on the 
Board of Health lactometer corresponds to 29° on the 
Quevenne lactometer, the zero mark showing in either 
case a specific gravity of 1, the degrees on the former 
lactometer may easily be changed into Quevenne lacto- 
meter degrees by multiplying by .29. To further aid in 
this transposition, table III is given in the Appendix, 
showing the readings of the two scales between 60° and 
120° on the Board of Health lactometer. 

112. Reading the lactometer. For determining the spe- 
cific gravity of milk in factories or private dairies, tin 
cylinders, 1^ inches in diameter and 10 inches 
high, with a base about four inches in diame- 
ter, are recommended (see fig. 39); another 
form of specific gravity cylinders, in use in 
chemical laboratories, is shown in lig. 40. 
The cylinder is filled with milk of a tempera- 
•ture ranging between 50° and 70° F., to 
within an inch of the top, and the lactometer 
is slowly lowered therein until it floats; it is 
left in the milk for about half a minute before 
lactometer and thermometer readings are 
taken, both to allow the escape of air which 
cmc gravity ^^^ ^^^^ niixed with the milk in pouring it 
cylinder. preparatory to the specific gravity determina- 
tion, and to allow the thermometer to adjust itself to the' 



98 Testing Milk and Its Products. 

temperature of the milk. The lactometer should 
not be left in the milk more than a minute before 
the reading is taken , as cream will very soon begin to 
rise on the milk, and the reading, if taken later, will be 
too high, as the bulb of the lactometer will be floating 
in partially skimmed milk (23). In reading the lac- 
tometer degree, the mark on the scale plainly visible 
through the upper portion of the meniscus of the milk 
should be noted. Owing to surface tension the milk in 
immediate contact with the lactometer stem will rise 
above the level of the surface in the cylinder, and this 
must be taken into consideration in reading the degrees. 
There is no need of reading closer than one-half of a lac- 
tometer degree in the practical work of a factory or a 
dairy. 

H3. Time of taking lactometer readings. The specific 
gravity of milk should not be determined until an hour 
or two after the milk has been drawn from the udder, 
as too low results are otherwise obtained (RecMageVs 
phenomenon).^ The cause of this phenomenon is not 
definitely understood; it may come from the escape of 
gases in the milk, or from changes occurring in the me- 
chanical condition of the nitrogenous components of the 
milk. The results obtained after a couple of hours will 
as a rule come about one degree higher than when the 
milk is cooled down directly after milking and its specific 
gravity then determined. 

114. Influence of bi-chromate on lactometer readings. 
When potassium bichromate is added to milk samples 
to preserve them from souring (188), the specific gravity 

1 Milchzeituag 1883, 419; Bulletin No. 43, Chem. Div., U. S. Department 
of Agriculture, p. 191; Analyst 1894, p 76. 



The Lactometer and Its Application. 99 

of the milk is thereby increased; with the quantity usu- 
ally added (J gram to a pint of milk) the increase amounts 
to about 1 lactometer degree, and this correction of lacto- 
meter readings should be made with milk samples pre- 
served in this manner. To avoid this error. Dr. Eichloff ^ 
recommends using a solution of bi-chromate in water 
(43 grams to 1 liter), the specifc gravity of which is 
1.032, or similar to that of average milk; 5 cc. of this so- 
lution is required for a pint of milk. No correction is 
necessary for the dilution with this small amount of liquid 
preservative. 

115. Cleaning of lactometer. The lactometer should be 
cleaned directly after using, by rinsing with cold water; 
it is then wiped dry with a clean cloth and placed in the 
case. 

Calculation of Milk Solids. 

116. A number of chemists have prepared formulas for 
the calculation of milk solids when the fat content and 
the specific gravity (lactometer reading) of the milk are 
known. By careful work with milk tester and lacto- 
meter it is possible by means of these formulas to deter- 
mine the composition of samples of milk with consider- 
able accuracy outside of, as well as in chemical laborator- 
ies. As the complete formulas given by various chemists 
(Behrend and Morgen, Clausnitzer and Mayer, Fleisch- 
mannn, Hehner and Richmond, Richmond, Babcock)^are 
very involved, and require rather lengthy calculations, 
tables facilitating the figuring have been prepared. The 
formulas in use at the present time, in this country and 



1 Technik der Milchprlifung, p. 98. 

2 Agricultural Science, vol. Ill, p. 139. 



L ofC. 



100 Testing Milk and Its Products. 

abroad, are those proposed by Fleischmann, Hehner and 
Eichmond, and Babcock. Babcock's formula is the one 
generally taught in American dairy schools and is there- 
fore given here; it forms the foundation of table VI for 
solids not fat in the Appendix. 

By the use of these tables the percents of solids not fat 
may be found, corresponding to lactometer readings from 
26 to 36, and to fat contents from to 6 per cent. The 
formula, as amended in 1895,^ is as follows, 8 being the 
specific gravity and/ the per cent, of fat in the milk. 

(100 S Sf \ 

100—1 0753 ^f -1 )(100— f ) 2.5 

The derivation of this formula is explained in the re- 
port referred to. 

117. Short formulas. The tables made up from this 
formula, giving the percentages of solids not fat corres- 
ponding to certain per cents, of fat and lactometer read- 
ings, are given in the Appendix. A careful examination 
of the same discloses the fact that the per cent, of solids 
not fat increases uniformly at the rate of .25 per cent, for 
each lactometer degree, and .02 per cent, for each per 
cent, of fat. This relation is expressed by the following 

simple formulas: 

Solids not fat^i L + -2 f 
Total solids=iL +1.2 f, 
L being the lactometer reading at 60° F. (specific gravity 
X 1000 — 1000), and/ the per cent, of fat in the milk. 

Rule: a, To find the per cent of solids not fat in milk, add 
two-tenths of the per cent, of fat to one-fourth of the lactometer 
reading, and 

b, To find the per cent, of total solids in milk, add, one and 
two-tenths times per cent, of fat to one-fourth of the lactometer 
reading. 

1 Wisconsin experiment station, twelfth report, page 120. 



The Lactometer and Its Application. 101 

These formulas and rules are easily remembered and 
can be quickly applied without the use of tables. The 
results obtained by using them do not differ more than 
.04 per cent, from those of the complete formula for 
milks containing up to 6 per cent, of fat, and may be 
safely relied upon in practical work. 

Adulteration of Milk. 

118. Methods of adulteration. The problem of deter- 
mining whether or not a sample of milk is adulterated 
becomes an important one in the work of milk inspectors 
and dairy- and food chemists. Managers of creameries 
and cheese factories are also sometimes interested in as- 
certaining possible adulterations in case of some patron's 
milk, although at present, since the general introduction 
of the Babcock test in factories and the payment for the 
milk on the basis of the amount of butter fat delivered, 
the temptation to water or skim the milk has been large- 
ly removed. In the city milk trade, especially in our 
larger cities, watered or skimmed milk is still frequently 
met with, in spite of the vigilance of their milk inspect- 
ors or officers of the city boards of health. 

When the origin of a suspected sample of milk is 
known, a second sample should, when possible, be taken on 
the premises by or in the presence of the inspector, and the 
composition of the two samples compared. If the sus- 
pected sample is considerably lower in fat content than 
the second, so-called control-sample, and has a normal 
per cent, of solids not fat, it is skimmed; if the solids not 
fat are below normal, it is watered; and if both these 
percentages are abnormally low, the sample is most 
likely both watered and skimmed (123). 



102 Testing Milk and Its Products. 

n9. Latitude of variation. In order to determine 
whether or not a sample of milk is skimmed or watered, 
or both skimmed and watered, the per cents, of fat and of 
solids not fat in the sample must be ascertained, and if a 
control -sample can be secured, these determinations for 
both samples compared. The proper latitude to be al- 
lowed for the natural variation in the composition of 
milk differs accordiug to the origin of the milk; in case 
of milk from single cows, the variations in fat content 
from day to day may exceed one per cent. , although under 
ordinary conditions the per cent, of fat in most cows' milk 
will not vary that much. The content of solids not fat 
is more constant, and rarely varies one-half of one per 
cent, from day to day with single cows. Cows in heat or 
sick cows may give milk differing considerably in com- 
position from normal milk.^ 

120. Mixed herd milk is of comparatively uniform com- 
position on consecutive days, and as most milk offered 
for sale or delivered to factories is of this kind, the task 
of the milk inspector is made considerably easier and 
more certain on this account. Daily variations in herd 
milk beyond one per cent, of fat and one-half per cent, of 
solids not fat, are suspicious and may be taken as fairly 
conclusive evidence of adulteration. This is especially 
true in case the control- sample shows a comparatively 
low content of fat or solids not fat (155). 

121. Legal standards. Where a control- sample cannot 
be taken, the legal standards of the various states for fat 
or solids in milk are used as a basis for calculating the 



1 

et seq 



Blythe, Foods, their Composition and Analysis, London, 1903, p. 250 



The Lactometer and Its Application. i03 

extent of adulteration of a sample of milk. A list of 
legal standards for milk in this country and abroad is 
given in the Appendix. These standards determine the 
limits below which the milk offered for sale within the 
respective states must not fall. Legally it matters not 
whether a sample of milk offered for sale has been 
skimmed or watered by the dealer or by the cow; in the 
latter case, the cows producing the milk are of a breed 
or a strain that has been bred persistently for quantity 
of milk, without regard to its quality. In most states 
the legal standard for the fat content of milk is 3 per 
cent, and for solids not fat 9 per cent. There are, how- 
ever, cows which some times produce milk containing only 
2.5 to 2.8 per cent, of fat, and less than 8.5 per cent, 
solids not fat. Such milk cannot therefore be legally 
sold in most states in the Union, and the farmer offering 
such milk for sale, even if he does not know the compo- 
sition of the milk produced by his cow, is as liable to 
prosecution as if he had directly watered the milk. By 
mixing the milk of several cows, the chances are that the 
mixed milk will contain more fat and solids not fat than 
called for by the legal standard; if such should not be 
the case, cows producing richer milk must be added to 
the herd so as to raise the quality of the herd milk up to 
the legal standard, or the cows giving very thin milk 
must be disposed of. 

122. The specific gravity of the milk solids. A calcula- 
tion of the specific gravity of the milk solids is of consid- 
erable assistance in interpreting the results of analyses 
of suspected milk samples. The milk solids vary but 
slightly in specific gravity, viz., between 1.25 and 1.34, 



104 Testing Milk and Ita Products. 

the richer milks having solids of low specific gravities. 
The specific gravity of the solids of railk is calculated by 
means of Fleischmann's formula 

t 



S: 



100 s- 100 
t — 



s 

-S^ being the sp. gr. of the milk solids, s that of the milk 
and t the total solids of the milk. 

Example: A sample of milk has been found to contain 13.0 

1.032- 
1.032 



per cent, of solids, sp. gr. 1.032; then ^^^^^|:^||^^^= 3.101 ; 13.0 



— 3.]01=r9.899; ^^^ = 1.31 = the specific gravity of the mi. k solids. 

The specific gravity of the solids does not change if 
the milk is watered, while it is increased when the milk 
is skimmed. If a sample of milk of the composition 
given in the preceding example had been watered so as 
to reduce the solids to 11.7 per cent, and the specific 
gravity to 1.0291 (as would be the case when 10 per cent, 
of water was added), we would again have/ by calcula- 
tion as above, S = 1.31. If, on the other hand, the milk 
was skimmed so as to reduce the solids to 11.7 per cent., 
thereby increasing the specific gravity of the milk to, 
say 1.035, we would have by substituting these values 
in the preceding formula, S = 1.41, showing conclusively 
that the milk had been skimmed. 

Addition of skim milk to whole milk would have the 
same effect as skimming, as regards the composition of 
the latter, and the specific gravity of its solids. 

The specific gravity of pure butter fat at 60° F. is .93, 
and of the fat free milk solids 1.5847 (Fleischmann). 
The solids of skim milk have a specific gravity of 1.56. 
Samples of whole milk, the solids of which have a spe- 



The Lactometer and Its Application. 105 

cific gravity above 1.34 are suspicious, and a specific 
gravity over 1.40 is couclusive evidence of skimming. 

To facilitate the calculation of the specific gravity of 
milk solids, table IV is given in the Appendix, showing 
at a glance the value of ^"^^~^"" for specific gravities be- 
tween 1.019 and 1.0869. An example will readily illus- 
trate the use of the table. 

Example: A sample of milk has a specific gravity of 1.0343 
and contains 12.25 per cent, solids. In table IV, we find in the 
horizontal line beginning with 1.034 under the column headed 
0.0003, the figure 3.316, which is the value for ^^^^~^^" when 
s= 1.0343. Introducing this value and that of the total solids 
in the formula, the calculation is 12.25-3.316=8.934; 12.25^ 
8.984=1.37. The specific gravity of the solids in this case 
therefore is 1.37. 

123. To recapitulate. Adulteration of milk by water- 
ing or skimming or both may be established by a com- 
parison of the composition of the suspected sample with 
that of a control-sample, or if none such can be obtained, 
with the legal standards. If the composition of the two 
samples varies appreciably, the milk has been adulteiated, 
and the character of the adulteration is shown from the 
following statement: 

//" the analysis of the suspected sample 
shows the milk is 

sp. gr. of milk | 

fat and solids not fat ( ^ watered 



sp. gr. of solids normal 

sp. gr. of milk and of solids }■,. . ) 

solids not fat j ^^ [-skimmed 

fat and solids low j 

sp. gr. of milk normal ") watered 

sp. gr. of solids, normal or high V and 

fat and solids not fat low ) skimmed 



106 Testing Milk and Its Products. 

The extent of the adulteration is determined as given 
below. 

124. Calculation of extent of adulteration/ In the fol- 
lowing formulas, per cents, found in the control -samples, 
if such are at hand, are always substituted for the legal 
standards. 

a. Skimming. — 1. If a sample of milk has been skim- 
med, the following formula will give the number of 
pounds of fat abstracted from 100 lbs. of milk: 

Fat abstracted = (x)= legal standard for fat — f, . (I) 
f being the per cent, of fat in the suspected sample. 

2. The following formula will give the per cent, of fat 
abstracted, calculated on the total quantity of fat origi- 
nally found in the milk: 

x=100 ^^^^^ .... (II) 

legal standard for fat 

b. Watering. — 1. If a sample is watered, the calcula- 
tions are most conveniently based on the percentage of 
solids not fat in the milk: 

Per cent, of foreign (extraneous) water in adulterated 

•n -.AA SXlOO .jrrx 

milk = 100— , r— — - — ^-. TT-z —— • ' • ^^^^) 

legal standard tor solids not lat 

S being the per cent, of solids not fat in the suspected 
sample. 

Example: A sample of milk contains 7.5 per cent, solids not 
fat; if the legal standard for solids not fat is 9 per cent., 

7 5 X 100 
100— - — Q = 16.7, shows the per cent, of extraneous water 

in the milk. 

2. Watering of milk may also be expressed in per cent, 
of water added to the original milk, by formula TV: 

1 Woll, Handbook for Farmers and Dairymen, New York, 1903, pp. 236-7. 



The Lactometer and Its Application. 107 

Per cent, water added to original milk 

_ 100 X leg. stand, for sol. not fat 

— (Xj — ^ iUU . (,!'') 

100 X 9 
In the example given above^ — ^— — — 100 = 20 per 

cent, of water was added to the original milk. 

c. Watering and skimming. — If a sample has been both 
watered and skimmed, the extent of watering is ascer- 
tained hj means of formula (III) or (IV), and the fat 
abstracted found according to the following formula: 

Per cent, fat abstracted = 

^ . , - • -, ^ .. . leg.stand.forsol.notfat^ „ .^^. 
(x):=leg. stand, for fat ^ Xf . (V) 

Example: A sample of milk contains 2.4 per cent, of fat and 
8.1 per cent, solids not fat; then 

Extraneous water in milk=100 '- — - — =10 per cent. 

9X 2 4 
Fat abstracted =3 -—^=.33 per cent. 

o. i 

100 l)s. of the milk contained 10 lbs. of extraneous waterand 
.33 lb. of fat had been skimmed from it. 

For methods of detection of other adulterations and of 
preservatives in dairy products, see Chapter X, 281 
et seq. 



CHAPTER YII. 
TESTING THE ACIDITY OP MILK AND CREAM. 

125. Cause of Acidity in Milk. Even directly after milk 
is drawn from the udder it will be found to have an acid 
reaction, when phenolphtalein is used as an indicator.^ 
The acidity in fresh milk is not due to the presence of 
free organic acit's in the milk, like lactic or citric acid, 
but to acid phosphates, and possibly also in part to free 
carbonic acid gas in the milk or to the acid reaction of 
casein. Even in case of so-called sweet milk, nearly 
fresh from the cow, a certain amount of acidity, viz., 
on the average about .07 per cenfc., is therefore found. 
When the milk is received at the factory it will rarely 
test less than .10 per cent, of acid, calculated as lactic 
acid; some patrons bring milk day after day that does 
not test over .15 per cent, of acid; that of others tests 
from .20 to .25 per cent., and some lots, although very 
rarely, will test as high as .3 of one per cent, of acid. 
It has been found that milk will not usually smell or 
taste sour or ^'turned," until it contains .30 to .35 per 
cent, of acid. 

126 The acidity in excess of that found normally in 
mili^ as drawn from the udder, is due to other causes 
than those described. Bacteriological examinations of 
milk from different sources and of the same milk at dif- 
ferent times have shown that there is a direct relation 



1 Freshly drawn milk shows an amphoteric reaction to litmus, i. e., it 
colots blue litmus paper red, and red litmus paper faintly blue. 



Testing the Acidity of Milk and Cream,. 109 

between the bacteria found in normal miH?, and its acid- 
ity; the larger the number of bacteria per unit of milk, 
the higher the acidity of the milk. The increase in the 
acidity of milk on standing is caused by the breaking- 
down of milk sugar into lactic acid through the influence 
of acid-forming bacteria. Since the bacteria get into the 
milk through a lack of cleanliness during the milking, or 
careless handling of the milk after the milking, or both, 
it follows- that an acidity test of new milk will give a 
good clue to the care bestowed in handling the milk. 
Such tests will show which patrons take good care of 
their milk and which do not wash their cans clean, or 
their hands and the udders of the co^s before milking, 
and have dirty ways generally in milking and caring for 
the milk. The acidity test is always higher in summer 
than in winter, and is generally high in case of milk 
kept for more than a day (Monday milk), or delivered 
after a warm, sultry day or night. The bacteria have a 
chance to multiply enormously in such milk, even if it 
be kept cooled down to 40°-50° F., and as a result con- 
siderable quantities of lactic acid have been formed. 
The determination of the acidity of fresh milk is ex- 
plained in detail below (143). 

127. Method of testing acidity. Methods of measuring 
the acidity or alkalinity of liquids by means of certain 
chemicals giving characteristic color reactions in the 
presence of acid or alkaline solutions (so-called volumetric 
methods of analysis) have been in use for many years in 
chemical laboratories. They were applied to milk as 
early as 1872 by Soxhlet,^ and the method worked out 
by Soxhlet and Henkel has since been in general use by 

1 Jour. f. prakt. Cbemie, 1872, p. 6, 19. 



110 Testing Milk and Its Products. 

European chemists. They measured out 50 cc. of milk 
to which was added 2 cc. of a 2 per cent, alcoholic solu- 
tion of phenolphtalein, and this was titrated with a one- 
fourth normal soda solution^ (see below). In this country, 
Dr. A. G. Manns in 1890 published the results of work 
done in the line of testing the acidity of milk and 
cream, ^ and the method of procedure and apparatus pro- 
posed by him has become known under the name of 
Manns^ test, and has been advertised as such by dealers 
in dairy supplies. 

128. Manns' test. The acid in milk or cream is meas- 
ured by using an alkali solution of certain strength, with 
an indicator which shows by a change of color in the 
milk when all its acid has been neutralized. Any of the 
alkalies, soda, patash, ammonia, lime or barium can be 
used for making the standard solution, but it requires 
the skill and apparatus of a chemist to prepare it of the 
proper strength. A one-tenth normal solution^ of caustic 
soda is the alkali solution used most frequently in 
determining the acidity of milk, and is the solution lab- 
eled Neutralize!' of the Manns' test. 



1 Fleischmann, Lehrb. d. Milchwirtschaft, 3rd ed., p. 57. 

2 Illinois experiment station, bulletin No. 9, 

3 Normal solutions, as a general rule, are prepared so that one liter 
shall contain the hydrogen equivalent of the active reagent weighed in 
grams (Sutton). Caustic soda (NaOH ) is made up of an atom each of 
sodium (Na), oxygen (O), and hydrogen (H); its molecular weight is 
therefore 

23 + 16 + 1 = 40 
Na O H 
A normal soda solution then is made by dissolving 40 grams of soda in 
water, making up the volume to 1000 cc; a one-tenth normal solution will 
contain one-tenth of this amount of soda, or 4 grams dissolved in one liter. 
One cubic centimeter of the latter solution will contain .004 gram of soda, 
and will neutralize .009 gram of lactic acid. The formula for lactic acid is 
CaHgOa (see page 16), and its molecular weight therefore 3x12+6x1+3x16 
=90. A one-tenth normal solution of lactic acid contains 9 grams per liter, 
and .009 gram per cubic centimeter. 



Testing the Acidity of Milk and Cream. Ill 

The indicator used is a solution of phenolphtalein, a 
light yellowish powder; its compounds with alkalies are 
red, in weak alkaline solutions pink colored, while its 
acid compounds are colorless. The phenolphtalein solu- 
tion used is prepared by dissolving 10 grams in 300 cc. 
of 90 per cent, of alcohol (Mohr). 

129. In testing the acidity of either milk or cream it 
is necessary to measure out with exactness the quantity 
of liquid to be tested; Manns recommended using a 60 ce. 
pipette. This amount of milk or cream is measured into 
a clean tin, porcelain or glass cup, a few drops of the 
phenolphtalein solution are added, and the Neutralizcr 
(or alkali solution) is cautiously dropped in from a bur- 
ette, the point at which the solution stands before any 
is drawn out being noted. By constant stirring during 
this operation it will be noticed that the pink color formed 
by the addition of even a drop of alkali solution will at 
first entirely disappear, but as more and more of the acid 
in the sample becomes neutralized, the color will disap- 
pear more slowly, until finally a point is reached when 
the pink color remains permanent for a time. 'Eo more 
alkali should be added after the first appearance of a 
uniform pink color in the sample. This color will fade 
and gradually disappear again on standing, owing to the 
effect of the carbonic acid on the air, to which phenol- 
phtalein is very sensitive. The amount of the alkali solu- 
tion used for the test is then obtained from the reading 
on the scales of the burette. The per cent, of acid in the 
sample is calculated by multiplying the number of cc. of 
alkali solution used, by .009 and dividing the product 
by the number of cc. of the sample tested, the quotient 
being multiplied by 100. 



112 Testing Milk and Its Products. 

^ .... c. c. alkalix.009 

Percent, acidity = , — - ^ , X 100 

c. c. sample tested 

If 50 cc. of cream required 32 cc. of alkali solution to 

produce a permanent pink color, the per cent, of acid in 

32 X 009 

the cream would be -^ X 100 = . 58 per cent. A part 

50 

of this calculation may be saved by using- a factor for 
multiplying the number of cc. of alkali added in each 
test. This factor is obtained by dividing 009 (the num- 
ber of grams of lactic acid neutralized by one cc. of alkali 
solution) by the number of cc. of sample tested, and mul- 
tiplying the quoticLt by 100. If a 50 cc. pipette is used 
for measuring the sample to be tested, the factor will be 
(.009^50) XlOO = . 018; if a 25 cc. pipette is used, the 
factor will be (.009-=-25) X 100 = . 036; and if a 20 cc. 
pipette is used, (.009^20) X 100 = . 045 will be the factor 
to be applied in calculating the per cent, of acidity, the 
number of cc. of alkali used being in all cases multiplied 
by the particular factor corresponding to the volume of 
the sample tested. 

130. If a Babcock milk test pipette is taken for meas- 
uring the milk or cream to be tested for acidity, the 
factor will be (.009^17.6) X 100 = . 051. This is so nearly 
.05 that sufficiently accurate results may be obtained by 
simply dividing the number of cc. used by two; the re- 
sult will be the tenths per cent, of acid in the sample tested, 
e. g., if 17.6 cc. of cream required 12 cc. of one-tenthnor- 
mal alkali to give the pink color, then the per cent, of 
acid is 12^2 = . 6 per cent. If one-fifth normal alkali is 
used for testing, the per cent, of acidity is shown directly 
by the number of cc. used (Vivian). 



Testing the Acidity of Milk and Cream. 



113 



131. Manns' testing outfit. The apparatus (see fig. 
41) and chemicals needed for testing the acidity of milk 
or cream by the so-called Manns' test in- 
clude one gallon one-tenth normal alkali 
solution 5 four ounces of an alcoholic solu- 
tion of phenolphtalein, one 50 cc. glass 
burette with stop- cock, one burette stand, 
and a pipette for measuring the sample. 
This outfit will make about 100 tests and 
is sold for $5.00.^ 

132. The Alkaline tablet test. Solid 
alkaline tablets were proposed by Far- 
rington in 1894, as a substitute for the 
liquid used in the Manns' test.^ It was 
found possible to mix a solid alkali car- 
bonate and coloring matter, and com- 
press the mixture into a femall tablet, 
which would contain an exact amount of 
alkali. The advantage of the tablets lies 
in the fact that they will keep far better 
than a standard alkali solution, and 
they can be easily and safely sent 
by mail; they also require less ap- 
paratus and are considerably 

Fig. 41. Apparatus used in 

Manns" test. cheaper than standard alkali solu- 

tions; 1000 of these tablets, costing $2.00, will make 
about 400 tests. ^ Similar alkaline tablets were placed 

1 Devarda's aeidimeter (Milchzeitung, 1896, p. 785) is based on the same 
principle as Manns' test; one-tenth soda solution is added tolOOcc. of milk 
in a glass-stoppered graduated flask, 2 cc. of a 4 per cent, phenolphtalein 
solution being used as an indicator. The graduations on the neck of the 
flask give the " degrees acidity " directly. 

2 Illinois experiment station, bulletin Ko. 32, April, 1894. 

3 The tablets are sold by dealers^inj^dairy'^supplies. 




114 



Testing Milk and Its Products. 



on tlie market in Europe at about the same time, viz., 
Stokes' Acidity Pellets in 1893, and Eichler's Sceurepillen 
(acid-pills) in 1895.^ 

Two methods of using the tablets have been proposed, 
one, for the titration (determination of acidity) of ripen- 
ing cream in the manufacture of sour- cream butter; and 
the other, for determining the approximate acidity of 
different lots of apparently sweet milk or cream. 

133. Determination of acidity in sour cream. The 
method is equally applicable for the determination of the 
acidity of sour cream, sour milk 
and butter-milk, but is most fre- 
quently employed in testing the 
acidity of ripening cream, to ex- 
amine whether or not the ripening 








Fig. 42. Apparatus used for determining the acidity of cream or milk. 

process has reached the proper stage for churning the 
cream. The apparatus used (see fig. 42) is as follows: 

1 Babcock 17.6 cc. pipette. 

1 white cup. 

1 Milchzeitung, 1895, pp. 513-16. 



Testing the Acidity of Milk and Cream. 115 

J 00 cc. graduated cylinders; it is well to provide two 
or thrf e of these^ although only one is strictly necessary. 

134. Preparation of the solution. The tablet solution 
formerly used was prepared by dissolving five tablets in 
50 cc. of water; with 20 cc. of cream each cubic centi- 
meter of this solution represents .017 per cent, of acid 
(lactic acid) in the sample tested. The amount of acid 
in a given sample is then obtained by multiplying the 
number of cubic centimeters of the tablet solution used 
by .017. 

135. According to a suggestion made by Mr. 0. L. 
Fitch/ the strength of the solution was changed in 
such a manner that the percentages of acidity are indi- 
cated directly by the number of cubic centimeter of tab- 
let solution used in each test. The solution may be 
made up in two ways, viz., by use of a 20 cc. or a 17.6 
cc. pipette. 

a. Use of 20 cc. pipette. When a 20 cc. pipette is used 
for measuring the sample to be tested, the tablet solution 
is prepared by dissolving one tablet for every 17 cc. of 
water; for five tablets 85 cc. of water are therefore taken. 
When made in this way, each cubic centimeter of solu- 
tion represents .01 per cent, of acid in the sample tested, 
10 cc. being equal to .10 per cent, acid, 32 cc. to .32 per 
cent., 65 cc. to .65 per cent., etc. 

b. Use of 17.6 cc. pipette. The 17.6 cc. Babcock milk 
test pipette may be used for measuring the sample for 
acidity testing, and the results read directly from the 
graduated cylinder, if the tablet solution is prepared by 
taking one tablet for every 19.5 cc. of water; five tablets 
are therefore dissolved in 97 cc. of water. 

1 Hoard's Dairyman, Sept. 3, 1897. 



116 Testing MilJc and Its Products. 

136. As cream during its ripening process under our 
conditions generally has from . 5 to . 6per cent, of acid be- 
fore it is ready to be churned, a 50 cc. cylinderful of tablet 
solution of this strength will not be sufficient to make a 
test of cream containing over .5 per cent, of acid, al- 
though it is enough for testing the cream up to this point 
during the ripening process. The acid- testing outfit 
should therefore contain a 100 cc. graduated cylinder in- 
stead of one of 50 cc. capacity, so that cream of any 
amount of acidity up to 1 per cent, can be tested. A 
tablet solution of the strength given has not only the 
advantage over the solution previously recommended 
(5 tablets to 50 cc. of water)^ of showing the per cent, of 
acidity directly, without tables or calculations, but being 
weaker, the unavoidable errors of determination are de- 
creased by its use. 

Equally accurate results may be obtained by using 
solutions made up according to method a or method b, ex- 
plained in the preceding ( 135) . The latter method (17. 6 
cc. cream, 5 tablets per 97 cc. of water) has, however, the 
advantage in point of economy of apparatus, since a 
17.6 cc. pipette is found in creameries and dairies with 
the Babcock test outfit and is therefore most likely 
already available for use in testing the acidity of cream. 
This method is therefore considered preferable and 
referred to as 

137. The standard solution. The preparation of this 
solution is as follows. Five tablets are placed in the 
100 cc. cylinder which is filled to the 97 cc. mark with 



1 Illinois experiment station, bulletin No. 32; Wisconsin experiment, 
station, bulletin No. 52. 



Testing the Acidity of Milk and Cream. 117 

clean soft water. ^ The cylinder is tightly corked, shaken 
and laid on its side, as the tablets will dissolve more 
quickly when the cylinder is placed in this position than 
when left upright with the tablets at the bottom. Several 
cylinders containing the tablet solution may be prepared 
at a time; as soon as one is emptied, tablets and water 
are again added, and the cylinder is corked and placed 
in a horizontal position. In this way fresh solutions 
ready for testing are always at hand. The cylinder is 
kept tightly corked while the tablets are dissolving, so 
that none of the liquid is lost by the shaking. It is well 
to put the tablets in the cylinder with water at night; 
the solution will then be ready for use in the morning. 
Excepting a flocculent residue of inert matter, ^'set- 
tlings," which will not dissolve, the tablets must all dis- 
appear in the solution before this is used. The strength 
of the tablet solution does not change perceptibly by 
standing, at least for one week. The only precaution nec- 
essary is to avoid evaporation of the solution by keeping 
the cylinders tightly corked. The solid tablets will not 
change if kept dry, any more than dry salt changes by age. 
138. Accuracy of the tablets. The tablets have been re- 
peatedly tested by chemists and found to be accurate 
and very uniform in composition. Tests made with the 
tablets according to the directions here given can be 
therefore relied on as correct. The alkali solution is very 
sensitive, however, and should not be measured in a cylin- 
der which has been previously used for measuring sulfu- 
ric acid, as the smallest drop or film of acid from a dish 

1 Condensed steam, or rain water should be used, and not hard or 
alkali water, since the impurities in these affect the strength of the 
tablet solution. 



118 Testing Milk and Its Products. 

or from the operator's fingers will change the standard 
strength of the tablet solution. 

139. Making the test. The cream to be tested is thor- 
oughly mixed, and 17.6 cc. are measured into the cup. 
The pipette is rinsed once with water, and the rinsings 
added to the cream in the cup. A few cc. of the tablet 
solution prepared as given above are now poured from 
the cylinder into the cream and mixed thoroughly with 
it by giving the cup a gentle rotary motion. The tablet 
solution is added in small quantities until a permanent 
pink color appears in the sample. The number of cc. of 
tablet solution which has been used to color the cream 
is now read off on the scale of the cylinder. 

In comparing the results of one test with another, the 
same shade of color should always be adopted. The 
most delicate point is the first change from pure white or 
light yellow to a uniform pink color which the sample 
shows when the acid contained therein has just been neu- 
tralized. This shade of color is easily recognized with a 
little practice. The pink color is not permanent unless 
a large excess of the alkaline solution has been added, on 
account of the influence of the carbonic acid of the air 
(129), and the operator should not therefore be led to 
believe by the reappearance of the white color after a 
time, that the point of neutralization was not already 
reached when the first uniform shade of pink was 
observed. 

140. Acidity of cream. 17.6 cc. of sweet cream is gen- 
arally neutralized by 15-20 cc. of this tablet solution, 
representing from .15 to .20 per cent, of acid. A mildly 
sour cream is colored by 35 cc. tablet solution, and a sour 



Testing the Acidity of Milk and Cream. 119 

cream ready for churning by about 50 to 60 cc. tablet solu- 
tion. As the cream ripens, its acidity increases. The 
rate of ripening depends largely on the temperature at 
which the cream is kept. Cream containing .5 to . 6 per 
cent, of acid will make such butter as our American 
market demands at the present time. Cream showing 
an acid test of .55 per cent, may not be too sour, but .65 
per cent, of acid is very near, if not on the danger line, 
since such cream is likely to make strong flavored, almost 
rancid btitter. Each lot of cream should be tested as 
soon as it is ready for ripening, and the result of the test 
will show whether the cream should be warmed or cooled 
in order to have it ready for churning at the time desired. 
Later tests will show the rate at which the ripening is 
progressing, and the time when the cream has reached 
the proper acidity for churning. 

I4L The influence of the richness of cream on the acid 
test has been studied by Professor Spillman,^ and others.^ 
Since the acidity developes in the cream serum, it follows 
that an acidity of, say .5 per cent, in a 40 per cent, 
cream represents a larger acidity than in 20 per cent. - 
cream, e. g. In the former case we have .5 gram of 
acid in 60 grams of serum ( =.83 per cent, of the serum) ; 
in the latter case .5 gram acid is found in 80 grams 
serum (:=.63 per cent, of the serum). Therefore, rich 
cream need not be ripened to as high a degree of acidity 
as thin cream. A table is given in the Iowa bulletin 
referred to, showing the relation between the richness 
and the acidity of cream. 



1 Washington experiment station, bulletin No. 32. 

2 Chicago Dairy Produce, April 21, 1900, p. 30; Iowa Expt. Sta., Bull. 52. 



120 



Testing MiTk and Its Products. 



h 



142. Spillman's cylinder. The graduated cylinder shown in 
fig. 48 was devised by Professor Spillman for use in testing the 
acidity of milk and cream with Farrington's alkaline tablets. 
The following directions are given for making 
tests with this piece of apparatus i^ 

"All that is needed in addition to the acid-test 
graduate shown in the accompanying illustra- 
tion, is a common prescriiDtion bottle of six or 
eight ounce capacity, and a package of Farring- 
ton's alkaline tablets. Fill the bottle with water 
and add one tablet for each ounce of water in 
the bottle. Shake the bottle frequently to aid 
in dissolving the tablets. 

''Making the test. In making the test, the 
acid-test graduate is filled to the zero mark with 
the milk or cream to be tested. The tablet solu- 
tion is then added, a little at a time, and the 



Fig, 43. Spill- graduate shaken after each addition, in order to 

man's cylinder, thoroughly mix the milk and the tablet solution. 

u,s6(i in d-Gtcr- 

mining the acid- ^^ shaking the graduate, give it a rotary motion 

ity of cream or to prevent spilling any of the liquid. Continue 

™^^^- adding the tablet solution until a permanent 

pink color can be detected in the milk. The level of the liquid 

in the graduate, measured by the scale on the graduate, will 

then be the per cent, of the acidity of the milk. It is best to 

stand the graduate on a piece of white paper, so. that the first 

pink coloration of the milk may be easily detected." 

143. Rapid estimation of the acidity of apparently sweet 

milk or cream, a, Milk. The alkaline tablet method offers 

a ready means of estimating the acidity of milk or cream 

that is still sweet to the taste. The selection of the best 

kinds of milk is especially important in pasteurizing milk 

or cream. Investigations have shown that milk which 

gives the highest acid test contains, as a rule, a larger 



1 Washington experiment station, bulletin No. 24. 



Testing the Acidity of Milk and Cream. 



121 



number of bacteria and spores not destroyed by pasteur- 
ization than does milk giving a low acid test (126)5 ^^^ 
acidity test may therefore be used to advantage for the 
purpose of selecting milk best adapted for pasteurization, 
as well as such as is to be retailed or used in the manu- 
facture of high-grade butter and cheese. 






Fig. 44. Apparatus used for rapid estimation of the acidity of appar- 
ently sweet milk or cream. 

In distinguishing milk fit for pasteurization purposes 
from that which is doubtful, an arbitrary standard of 
two- tenths of one per cent, of acid may be taken as the 
upper limit for milk of the former kind. The appara- 
tus used in making this test is shown in the accom- 
panying illustration (fig. 44), and consists of a white 
teacupj a four-, six-, or eight-ounce bottle, and a E'o. 10 
brass cartridge shell, or a similar measure. A solution 
of the tablets in water is first prepared, one tablet being 



122 Testing Milk and lis Products. 

always added to each ounce of water: four tablets in a 
four-ounce bottle; six, in a six-ounce bottle, etc., the 
amount of tablet solution prepared depending on the 
number of tests to be made at a time. The bottle is filled 
up to its neck with clean, soft water, and the solution 
prepared in the manner previously given (137). 

144. Operating the test. As each lot of milk is brought 
to the creamery in the morning and poured into the 
weigh can, it is weighed and the cartridge- shell dipper 
filled with the milk is emptied into the white cup. The 
same or another No. 10 shell is now filled twice with the 
tablet solution and emptied into the milk in the cup. 
Instead of dipping twice with one measure or a No. 10 
shell, a tin measure can be made holding as much as two 
No. 10 shells, or the tablet solution may be made of 
double strength, that is, two tablets to each ounce of 
water and the same sized measure for both the milk and 
the tablet solution used. The liquids are then mixed 
in the cup by giving this a quick, rotary motion, and 
the color of the mixture noticed. If the milk remains 
white it contains more than two-tenths of one per cent, 
of acid and should not be used for pasteurization. If it 
is colored after having been thoroughly mixed with two 
measures of tablet solution, it contains less than this 
amount of acid and may, as far as acidity goes, be 
safely used for pasteurization or for any other purpose 
which requires thoroughly sweet milk. The shade of 
color obtained will vary with different lots of milk ; the 
sweetest milk will be most highly colored, but a milk 
retaining even a faint pink color with two measures of 
tablet solution or one measure of the double strength 



Testing the Acidity of Milk and Cream. 123 

solution to one measure of milk contains less than .2 per 
cent, of acid. 

By proceeding in the vmanner described, the man re- 
ceiving and inspecting the milk at the factory weigh- can 
is able to test the acidity of the milk delivered nearly as 
quickly as he can weigh it; and according to the results 
of the test he can send the milk to the general delivery 
vat or to the pasteurization vat, as the weigh can may 
be provided ^ith two conductor spouts. 

145. Size of measure necessary. It is not necessary to 
use a No. 10 shell for a measure in working the preced- 
ing method; one of any convenient size that can be filled 
accurately and quickly, will answer the purpose equally 
well, if a measure of the same size is used for both the 
sample and the tablet solution. Each measureful of tab- 
let solution made up as directed, will in this case repre- 
sent one-tenth per cent, of acid in the sample tested. 

146. b, Cream. Cream can be tested in the way already 
described for testing the acidity of fresh milk, by adding 
to one measureful of cream in the cup as many measures 
of tablet solution as are necessary to change the color of 
the cream when the two liquids are thoroughly mixed. 
If one measure of tablet solution colors one measure of 
cream, this contains less than .1 per cent, acid; if five 
measures of tablet solution are required, the cream con- 
tains about .5 per cent, acid, etc. By proceeding in the 
manner described, the operator can estimate the acidity 
to within .05 per cent, of acid, if half measures of tablet 
solution are added. The results thus obtained are suffi- 
ciently delicate for all practical purposes. 



124 Testing MilTc and Its Products. 

147. Detecting boracic-acid preservatives in milk. The applica- 
tion of the alkaline tablet test for detecting boracic acid in milk 
was first discussed in bulletin No. 52 of Wisconsin experiment 
station. The acidity of the milk is increased by the addition 
of boracic acid, but neither the odor nor the taste of the milk is 
afTected thereby. By adding to sweet milk the amount of bor- 
acic acid which will keep it sweet for 36 hours, its acidity may 
be increased to .35 per cent., in a sample of milk which previ- 
ously tested perhaps only .15 per cent. acid. 

As before stated, unadulterated milk will usually smell or taste 
sour or "turned," when it contains .30-35 per <*ent. acid (118); 
milk testing as high as this limit, which neither smells nor 
tastes sour in any way, is therefore in all probability adulter- 
ated with some preparation containing boracic acid or a similar 
compound. 

148. "Alkaline tabs." These are not the alkaline tablets, but a 
substitute which was put on the market by a New York firm. 
The outfit furnished consisted of four packages of paper discs 
made of filter paper, each of about the size of an old-style cop- 
per cent; two packages of square paper; one glass of about 10 cc. 
capacity, and one small glass bottle. An investigation of 
these "Tabs" soon disclosed the fact that they were entirely 
inaccurate, and that no dependence could therefore be put on 
the results obtained by their use. 



CHAPTEE VIII. 
TESTING THE PURITY OP MILK. 

149. The Wisconsin curd test. Cheese makers are often 
troubled with so-called floating or gassy curds which 
produce cheese defective in flavor and texture. These 
faults are usually caused by some particular lot of milk 
containing impurities that cannot be detected by ordi- 
nary means of inspection. The Wisconsin curd test is 
used to detect the source of these defects and thus enable 
the cheese maker to exclude the milk from the particular 
farm or cow to which the trouble is traced. This test is 
similar in principle to tests that have for many years 
past been in use in cheese-makiDg districts in Europe, 
notably in Switzerland/ but was worked oat independ- 
ently at the Wisconsin Dairy School in 1895 and has 
become generally known as the ^'Wisconsin Curd Test" 
from the description of it in the report of the Wisconsin 
experiment station for 1895.^ 

The apparatus used for the test was greatly improved 
in 1898, and a description of the improved test is given 
in bulletin No. 67 and the annual report of this Station 
for 1898, '^ from which source the accompanying illustra- 
tions are taken (see figs. 44 and 45). 

150. Method of making the test. Pint glass jars, thor- 
oughly cleaned and sterilized with live steam, are pro- 

1 Herz, Unters. d. Kuhmilch, Berlin, 1889, p. 87 ; Siats, Unters. landw. 
wicht. Stoffe, 1897, pp. 129-131. 

2 Twelfth report, p. 148. 

3 Fifteenth report, pp. 47-53. 



126 



Testing Milk and Its Products. 



vided; they are plainly numbered or tagged, one jar 
being provided for each lot of milk to be tested. The 
jars are filled about two-thirds full with milk from the 
various sources; it is not necessary to take any exact 
quantity; they are then placed in a water tank, the water 




Fig. 44. The Wisconsin curd test. 1, Test jars draining: 2, whey outlet; 
3, test jars in water tank; 4, test jars in parts; 5, stop cock for water; 6, 
stand to support cover. 




Fig. 45. Cross-section of the Wisconsin curd test. T J-TJ", testing jars 
Showing different stages of test; WL, water line; M, milk; F, frame; WS, 
stand to support cover; AI drain holes; WO, water outlet; DP, drain pail. 



Testing the Purity of Milk. 127 

of which is heated until the milk in the jars has a tem- 
perature of 98° F. The thermometer used must not be 
transferred from one sample to another, unless special 
precautions are taken, for fear of contaminating the pure 
lots of milk by impure ones. 

When the milk has reached a temperature of 98°, add 
to each sample ten drops of rennet extract, and mix by 
giving the jar a rotary motion. The milk is thus cur- 
dled, and the curd allowed to stand for about twenty 
minutes until it is firm. It is then cut fine with a case 
knife, and after settling, the whey is poured off. The 
best tests are made when the separation of the whey is 
most complete. By allowing the samples to stand for a 
short time, more whey can be poured off, and the curd 
thereby rendered firmer. The water around the jars is 
kept at a temperature of 98°, the vat is covered, and the 
curds allowed to ferment in the sample jars for six to 
twelve hours. 

During this time the impurities in any particular sam- 
ple will cause gases to be developed in the curds so that 
by examining these, by smelling of them and cutting 
them with a sharp knife, those having a bad flavor, or a 
spongy or in any way abnormal texture may be easily 
detected, and the milk from which it was made, thereby 
determined. 

151. By proceeding in the same way with the milk 
from the different cows in a herd, the mixed milk of 
which produced'abnormal curds, the source of contami- 
nation in the herd may be located. Very often the 
trouble will be found to come from the cows' drinking 



128 Testing Milk and Its Products. 

foul stagnant water or from fermenting matter in the 
stable. In the former case the pond or marsh must be 
fenced off, or the cows kept away from it in other ways; 
in the latter, a thorough cleaning and disinfection of the 
premises are required. If the milk of a single cow is 
the source of contamination, it must be kept by itself, 
until the milk is again normal; under such conditions 
the milk from the healthy cows may, of course, safely be 
sent to the factory. 

152. The fermentation test. The Gerber fermentation test (see 
fig. 46) furnishes a convenient method for examining the purity 
of different lots of milk. The test consists of a tin tank which 
can be heated by means of a small lamp, and into which a rack 
fits, holding a certain 
number of cylindrical 
glass tubes; these are all 
numbered and provided 
with a mark and a tin 
cover. In making the 
test, the tubes are filled 
to the mark with milk, 
the number of each tube 
being recorded in a note 
book, opposite the name 

of the particular patron whose milk was placed therein. The 
tubes in the rack are put in the tank, which is two-thirds full 
of water; the temperature of the water is kept at 104-106° F. for 
six hours, when the rack is taken out, the tubes gently shaken, 
and the appearance of the milk, its odor, taste, etc, carefully 
noted in each case. 

The tubes are then again heated in the tank at the same 
temperature as before, for another six hours, when observations 
of the appearance of the milk in each tube are once more taken. 




Fig. 46. The Gerber fermentation test. 



1 Die praktische Milchpriifung, p. 85. 



Testing the Purity of Milk. 



129 



The tainted milk may then easily be discovered by the abnor- 
mal coagulation of the sample. According to Gerber/ good and 
properly handled milk should not coagulate in less than twelve 
hours, when kept under the conditions described, nor show 
anything abnormal when coagulated. Milk from sick cows 
and from cows in heat, or with diseased udders, will always 
coagulate in less than twelve hours. If the milk does not 
curdle within a day or two, it should be tested for preserva- 
tives (290). 

153. The Monrad rennet test is used by cheese makers 
for determining the ripeness of milk. Fig. 47 shows the 

apparatus used in the test. 
5 cc. of rennet extract is 
measured by means of a pip- 
ette into a 50 cc. flask j the 
pipette is rinsed with water 
and the flask filled to the mark 
with water. 160 cc. of milk 
is now measured into the tin 
basin from the cylinder and 
slowly heated to exactly 86° 
F. 5 cc. of the diluted rennet 
solution is then quickly added 
to the warm milk and the 
time required for coagulation 
noted. ^ Milk sufficiently ripe 
for Cheddar cheese making 
will coagulate in 30-60 sec- 
onds, according to the strength of the rennet extract 
used. 




Fig. 47. The Monrad rennet test. 



1 Die praktische Milchpriifung, p. 85. 

2 Decker, Cheese Making, 1900, p, 36. 



130 



Testing Milk and Its Products. 



154. The Marschall rennet test is used for the same 
purpose as the Monrad test. The time required for 
coagulating the milk is shown directly by a scale given 

on the apparatus (fig. 
48). 

The directions for this 
test are as follows: Fill 
the small glass with pure 
water up to the mark, 
pour into it one cc. of ren- 
net extract and rinse the 
pipette in the same 
water. Fill the tin cup 
with milk to the zero mark, add the rennet, mix thor- 
oughly and allow it to stand. The ripeness of different 
samples of milk is shown by the amount that flows out 
before the milk coagulates. 




Fig. 48. The Marschall renneftest. 



OHAPTEE IX. 
TESTING MILK ON THE FARH. 

155. Variations in milk of single cows. The variations 
in the tests of milk of single cows from milking to milk- 
ing or from day to day, are greater than many cow- 
owners suspect. There seems to be no uniformity in this 
variation, except that the quality of the milk produced 
generally improves with the progress of the period of 
lactation 5 even this may not be noticeable, however, 
except when the averages of a number of tests made at 
different stages during the lactation period are compared 
with each other. When a cow gives her maximum 
quantity of milk, shortly after calving, the quality of 
her milk is generally poorer (by one per cent, of fat or 
less) than when she is drying off. Strippers' milk is 
therefore as a rule richer in fat than the milk of fresh 
cows. 

156. By testing separately every milking of a number 
of cows through their whole period of lactation, the 
results obtained have seemed to warrant the following 
conclusions in regard to the variations in the test of the 
milk from single cows, and it is believed that these con- 
clusions allow of generalization.^ 

1. Some cows yield milk that tests about the same at 



1 Illinois experiment station, bulletin No. 24. 



132 Testing Milk and Its Products. 

every milking, and generally give a uniform quantity of 
milk from day to day. 

2. Other cows give milk that varies in an unexplain 
able way from one milking to another. Neither the 
morning nor the evening milking is always the richer, 
and even if the interval between the two milkings is 
exactly the same, the quality as well as the quantity of 
milk produced will vary considerably. Such cows are 
mostly of a nervous, excitable temperament, and are 
easily affected by changes in feed, drink, or surrounding 
conditions. 

3. The milk of a sick cow, or of a cow in heat, as a 
rule, tests higher than when the cow is in a normal con- 
dition; the milk yield generally decreases under such 
conditions; marked exceptions to this rule have, how- 
ever, been observed. 

4. Half-starved or underfed cows may give a small 
yield of milk testing higher than when the cows are 
properly nourished, probably on account of an accompa- 
nying feverish condition of the animal. The milk is, 
however, more generally of an abnormally low fat con- 
tent, which may be readily increased to the normal per 
cent, of fat by liberal feeding. 

5. Fat is the most variable constituent of milk, while 
the solids not fat vary within comparatively narrow 
limits. The summary of the analyses of more than 2400 
American samples of milk calculated by Cooke^ shows 
that while the fat content varies from 3.07 to 6.00 per 
cent., that of casein and albumen varies only from 2.92 
to 4.30 per cent., or less than one and one-half per cent, 

1 Vermont experiment station, report for 1890, p. 97. 



Testing Milk on the Farm. 133 

and the milk sugar and ash content increases but little 
(about .69 per cent.) within the range given. 

6. A test of only one milking may give a very erro- 
neous impression of the average quality of a certain 
cow's milk. A composite sample (see 175) taken from 
four or more successive milkings will represent the 
average quality of the milk which a cow produces at 
the time of sampling. 

157. The variations that may occur in testing the milk 
of single cows, are illustrated by the following figures 
obtained in an experiment made at the Illinois experi- 
ment station, ^ in which the milk of each of six cows was 
weighed and analyzed daily during the whole period of 
lactation. Among the cows were pure- bred Jerseys, 
Shorthorns and Holsteins, the cows being from three to 
eight years of age and varying in weight from 850 to 
1350 lbs. During a period of two months of the year, 
the cows were fed a heavy grain ration consisting of 12 
Hbs. of corn and cob meal, six lbs. of wheat bran, and six 
lbs. of linseed meal, per day per head. This system of 
feeding was tried for the purpose of increasing, if possi- 
ble, the richness of the milk. The influence of this heavy 
grain feed, as well as that of the first pasture grass feed, 
on the quality and the quantity of the milk produced is 
shown in the following table, which gives the complete 
average data for one of the cows (No. 3). The records 
of the other cows are given in the publication referred 
to; they were similar to the one here given in so far as 
variations in quality are concerned. 



1 Bulletin No. 24. 



134 



Testing Milk and Its Products. 



Average results obtained in weighing and testing a cow^s milk 
daily during one period of lactation. 





bo 

u 


Daily Milk 
yield. 


Test of one day's 
milk. 


Yield of fat per 
day. 


MONTH. 


r 




-►J 
a> CO 

3 




1^ 


1"^ 


be 

U 

< 


1. 


3 


December.... 

January 

February 

March 

April 


920 
927 
1035 
1047 
1054 
1079 
1105 
1180 
1130 


12.1 
16.0 
16.1 
14.3 
13.8 
14 5 
12.1 
9.3 
6.4 


16.0 
17.7 
17.7 
16.0 
16 5 
17.2 
14.0 
12.2 
9.3 


10.0 
14.0 
13 5 
12.5 
11.5 
10.0 
9.2 
6.0 
3.5 


38 
3.7 
3.6 
3.8 
40 
3.8 
3.9 
4.2 
4.7 


4.9 
4.6 

5.8 
4.7 
5.8 
4.6 
4.6 
6.2 
7.9 


3.0 

2.7 
3.2 
3.4 
SO 
3.4 
3.2 
2.8 
2.9 


.46 
.59 
.58 
.54 
.55 
.55 
.47 
.39 
.30 


.60 

.76 
.84 
.61 
.72 
.70 
.57 
.60 
.50 


.34 

.44 

.5i: 

.50 

.46 


May 


.44 


June 


.85 


July 


.271 


August 


.16 







158. The average test of this cow' s milk for her whole 
period of lactation was 3.8 per cent, of fat (i. e., the total 
quantity of fat produced -=- total milk yield X 100); twice 
during this time the milk of the cow tested as high 
as 5.8 per cent., and once as low as 2. 7 percent. The 
average weight of milk produced per day by the cow 
was 14 lbs. ; this multiplied by her average test, 3. 8, 
shows that she produced on the average .53 lbs., or about 
one-half of a pound, of butter fat per day during her lac- 
tation period. If, however, her butter-producing capac- 
ity had been judged by the test of her milk for one day 
only, this test might have been made either on the day 
when her milk tested 5.8 per cent., or when it was as low 
as 2. 7 per cent. Both of these tests were made in mid- 
winter when the cow gave about 16 lbs. of milk a day. 
Multiplying this quantity by . 058 gives . 93 lbs. of fat, and 
by .027 gives .43 lbs. of fat. Either result might show 



TestinglMilk on the Farm. 135 

the butter fat produced by the cow on certain days, but 
neither gives a correct record of her actual average daily 
performance for this lactation period. 

A sufficient number and variety of tests of the milk of 
many cows have been made to prove that there is no 
definite regularity in the daily variations in the richness 
of the milk of single cows. The only change in the qual- 
ity of milk common to all cows is, as stated, the natural 
increase in fat content as the cows are drying off, and 
even in this case the improvement in the quality of the 
milk sometimes does not occur until the milk yield has 
dwindled down very materially. 

159. Causes of variations in fat content. The quality of 
a cow's milk is as a rule decidedly influenced by the fol- 
lowing conditions: 

Length of interval between milkings. 

Change of feed. 

Change of milkers. 

Rapidity of milking. 

Rough treatment. 

Exposure to rain or bad weather. 

Unusual excitement or sickness. 

160. Disturbances like those enumerated frequently 
increase the richness of the milk for one, and sometimes 
for several milkings, but a decrease in quality follows 
during the reaction or the gradual return to normal con- 
ditions, and taken as a whole there is a considerable 
falling off in the total production of milk and butter fat 
by the cow, on account of the nervous excitement which 
she has gone through. Aside from changes due to well- 
definable causes like those given above, the quality of 



136 Testing Milk and Its Products. 

some cows' milk will often change very considerably 
without any apparent cause. The dairyman who is in 
the habit of making tests of the milk of his individual 
cows at regular intervals will have abundant material 
for study in the results obtained, and he will soon be 
able to tell from the tests made, if these are continued 
for several days, whether or not the cows are in a normal 
healthy condition or have been subjected to excitement 
or abuse in any way. 

161. Number of tests required during a period of lacta- 
tion in testing cows. The daily records of the six cows 
referred to on page 133 give data for comparing their 
total production of milk and butter fat during one period 
of lactation, as found from the daily weights and tests 
of their milk, with the total amount calculated from 
weights and tests made at intervals of 7, 10, 15 or 30 
days. The averages of all results obtained with each of 
the six C0W3 show that weighing and testing the milk of 
a cow every seventh day gave 98 per cent, of the total 
milk and butter fat, which according to her daily record 
was the total product. Tests made once in two weeks 
gave 97.6 per cent, of the total milk, and 98.5 per cent, 
of the total butter fat, and tests made once a month, or 
only ten times during the period of lactation, gave 96.4 
per cent, of the total milk, and 97 per cent, of the total 
production of butter fat. 

162. The record of one of the cows will show how 
these calculations are made: It was found from the 
daily weights and tests that cow No. 1, in one lactation 
period of 307 days, gave 5,044 lbs. of milk which con- 
tained 254 lbs. of butter fat. Selecting every thirtieth 



Testing Milk on the Farm. 



137 



day of her record as testing day, the total production of 
milk and fat is shown to be as follows: 

Production of milk and butter fat per day. 



Testing day. 


Weight of milk. 


Test of milk. 


Yield of butter fat. 


Nov. 4 


lbs. 
20.5 
18.7 
17.7 
20.0 
18.2 
19.5 
17.7 
13.1 
12.2 
3.2 


per cent. 
4.7 
4.6 
4.9 
4.5 
4.7 
4.4 
4.8 
5.5 
6.2 
7.2 


lbs. 
96 


Dec. 4 


86 


Jan. 3 


86 


Feb. 2 


.90 


Mar. 3. ... . 


86 


April 2 


81 


May 2 

June 1 


.85 
72 


July 1 

July 31 


.76 
.23 


Total 


160.8 lbs. 
16.08 nbs. 




7.81 ll3s. 


Average per day. 


4.85 


.78 lbs. 



The average daily production of the cow, according to 
the figures given in the preceding table, was about 
16 lbs. of milk, containing . 78 lbs. of butter fat. Multi- 
plying these figures by 307, the number of days during 
which the cow was milked, gives 4,912 lbs. of milk and 
240 lbs. of fat. This is 132 lbs. of milk and 14 lbs. of fat 
less than the total weights of milk and butter fat, as 
found by the daily weights and tests, or 2.8 and 5.5 per 
cent, less, for milk- and fat production, respectively. 
This is, however, calculated from only ten single weights 
and tests, while it required over 600 weighings and 300 
tests of the milk to obtain the exact amount. 

Similar calculations from the records of the other cows 
gave fully as close results, showing that quite satisfac- 
tory data as to the total production of milk and butter 



138 



Testing Milk and Its Products. 



of a cow may be obtained by making correct weighings 
and tests of her full day's milk once every thirty days. 

163. When to test a cow.^ The Vermont experiment 
station for several years made a special study of the ques- 
tion when a cow should be tested in order to give a correct 
idea of the whole year' s performance, when only one or two 
tests are to be made during the lactation period. ^ The re- 
sults obtained may be briefly summarized as follows: 

a. As to quality of milk produced. If two tests of each 
cow's milk are to be made during the same lactation 
period, it is recommended to take composite samples at 
the intervals given below. 



For spring cows, 
For summer " 
For fall " 



FIRST SAMPLE. 



6 weeks after calving. 

8 " " 

8-10 " " " 



SECOND SAMPLE. 



6 ^-7 J mos. after calving. 

6 -7 " " " 

5i-7 " " " 



If only one test is to be made, approximately correct re- 
sults may be obtained by testing the milk during the sixth 
month from calving, in case of spring cows; during the 
third to fifth month in case of summer- calving cows, and 
during the fifth to seventh month for fall- calving cows. 

In all cases composite samples of the milk for at least 
four days should be taken (165). ^' The test of a single 
sample, drawn from a single milking or day, will not of 
necessity, or indeed usually give trustworthy results." 

1 H. B. Gurler in American Dairying, p. 18, suggests that three months 
after calving a cow's milk may be weighed for a week and a composite 
sample tested. The average weight of butter fat produced per day is cal- 
culated and this average figure multiplied by 252 or the number of days in 
8.4 months. It is assumed that a cow gives milk more than 8.4 months 
and the quantity produced beyond this time will bring the production 
during the last 2.4 months up to the same average per month as in the 
first six months. 

2 Sixth report, 1882, p. 106; Ninth report, 1895, p. 176. 



Testing Milk on the Farm. 



139 



b. As to quantity of milk produced. The milk may be 
weighed for four days in the middle of the month, and 
the entire month's yield obtained with considerable 
accuracy (barring sickness and drying off), by multiply- 
ing the sum by 7, 1^ or 7f , according to the number of 
days in the different months. The weighing is most 
readily done by means of a spring balance, 
the hand of which is set back so that the 
empty pail brings it to zero (fig. 50). If 
several pails are to be used, they should 
first be made to weigh the same by putting 
a little solder on the lighter pails. Milk 
scales which weigh and automatically reg- 
ister the yield of milk from twenty cows 
have been placed on the market, but no 
perfectly satisfactory device of this kind 
has yet been brought out, so far as is known 
to the authors. 

164. Sampling milk of single cows. . In 
sampling the milk of single cows, all the 
milk obtained at the milking must be carefully mixed, 
by pouring it from one vessel to another a few times, or 
stirring it thoroughly by means of a dipper moved up 
and down, as well as horizontally, in the pail or can in 
which it is held; the sample for testing purposes is then 
taken at once. A correct sample of a cow's milk cannot 
be obtained by milking directly into a small bottle from 
one teat, or by filling the bottle with a little milk from 
each teat, or by taking some of the first, middle and last 
milk drawn from the udder. Such samples cannot pos- 
sibly represent the quality of the milk of one entire milk- 




FiG.50. Milk 
Scale. 



140 Testing Milk and Its Products. 

ing, since there is as much diiference betwen the first and 
the last portions of a milking, as between milk and cream/ 
Lack of care in taking a fair sample is the cause of many- 
surprising results obtained in testing milk of single cows. 
165. When a cow is to be tested, she should be milked 
dry the last milking previous to the day when the test is 
to be made. The entire quantity of milk obtained at each 
milking is mixed and sampled separately. On account of 
the variation in the composition of the milk, a number of 
tests of successive milkings must be made. As this in- 
volves considerable labor, the plan of taking composite 
samples is preferable; the method of composite sampling 
and testing is explained in detail under the second sub- 
division of Chapter X (176) ; suffice it here to say that the 
method followed in case of single cows' or herd milk is 
to take about an ounce of the thoroughly mixed milk of 
each milking; this is placed in a pint or quart fruit jar 
containing a small quantity of some preservative, prefer- 
ably about one-half a gram (8 grains) of powdered potas- 
sium bi-chromate. If a number of composite samples of 
the milk of single cows are taken, each jar should be 
labeled with the number or name of the particular cow. 
Composite tests are generally taken for four days or for 
a week. If continued for a week, the jars will contain 
at the end of this time a mixture of the milk of fourteen 
milkings. The composite sample is then carefully 
mixed by pouring it gently a few times from one jar to an- 
other, and is tested in the ordinary manner. The result 
of this test shows the average quality of the milk pro- 



1 Woll, Handbook for Farmers and Dairymen, p. 194; Agricultural 
Science, 6, pp. 540-42. 



Testing Milk on the Farm. 141 

duced by the cow during the time the milk was sampled. 

166. As the amounts as well as the quality of the milk 
produced by single cows vary somewhat from day to day 
and from milking to milking, it is desirable in testing 
single cows, especially when the test includes only a few 
days, to take a proportionate part (an aliquot) of each 
milking for the composite test sample. This is easily done 
by means of a Scovell samj)ling tube, the use of which 
is explained in another place (180), or by a 25 cc. pi- 
pette divided into yi^ cc. ] in using the latter apparatus as 
many cubic centimeters and tenths of a cubic centimeter 
of milk are conveniently taken each time for the com- 
posite sample as the weight of milk in pounds and tenths 
of a pound produced by the cow.^ 

The opinion is often expressed that a considerable error 
is introduced by measuring out milk warm from the cow 
for the Babcock test, since milk expands on being warmed, 
and a too small quantity is obtained in this manner. By 
calculation of the expansion of milk between different 
temperatures it is found that 1 cc. of milk at 17.5° C. 
(room temperature) will have a volume of 1.006289 cc. 
at 37° C. (blood-heat), i. e., an error of less than .03 per 
cent, is introduced by measuring out milk of ordinary 
quality at the latter temperature. While the temperature 
has therefore practically no importance, the air incorpo- 
rated in the milk during the milking process will introduce 
an appreciable error in the testing, and samples of milk 
should therefore be left for an hour or more after milking 
before the test samples are taken. By this time the specific 
gravity of the samples can also be correctly taken (113). 

1 Decker, Wis. experiment station, report XVI. 



142 



Testing Milk and Its Products. 



167. Size of the testing sample. Four ounces is a suffi- 
cient quantity for a sample of milk if it is desired to de- 
termine its per cent, of fat only; if the milk is to be tested 
with a lactometer, when adulteration is suspected, as 
much as a pint is needed for a sample. If this sample of 
milk is put into a bottle and carried or sent away from 
the farm to be tested, the bottle should be filled with milk 
clear up to the cork to prevent a partial churning of 
butter in the sample during transportation (30). 

168. Variations in herd milk. While considerable vari- 
ations in the quality of milk of single cows are often met 
with, a mixture of the milk of several cows, or of a whole 
herd is comparatively uniform from day today; the indi- 
vidual differences tend to balance each other so that vari- 
ations, when they do occur, are less marked than in case 
of milk of single cows. There are, however, at times 
marked variations also in the test of herd milk on suc- 
cessive days; the following figures from the dairy tests 
conducted at the World' s Columbian Exposition in Chi- 
cago in 1893 illustrate the correctness of this statement. 
The test included twenty-five Jersey and Guernsey cows 
each and twenty- four Shorthorn cows. 

Tests of herd milk on successive days. 



DATE. 


Jersey. 


Guernsey. 


Shorthorn. 


July 16, 1893 


4.8 per cent. 

5.0 

4.7 " 

4.6 

5.0 


4. 6 per cent. 

4.5 

4.4 " 

4.6 

4.5 


3. 8 per cent. 

3.8 " 


July 17, 1893 


July 18, 1893 

July 19, 1893 


3.8 " 
3.7 " 


July 20, 1893 


3.8 " 







Testing Milk on the Farm, 143 

On July 17, 1893, the mixed milk of the Jersey cows 
tested two-tenths of one per cent, higher than on the pre- 
ceding day; the Guernsey herd milk tested one-tenth of 
one per cent, lower, while the Shorthorn milk did not 
change in composition; comparing the tests, on July 19 
and 20, we find that the Jersey and Shorthorn milk tested 
four-tenths and one-tenth of one per cent, higher, respect- 
ively, on the latter day than on the former, and the 
Guernsey milk tested one-tenth of one per cent, lower. 

169. Ranges in variations of herd milk. According to 
Fleischmanu,^ the composition of herd milk may on single 
days vary from the average values for the year expressed 
in per cent, of the latter, as follows: 

The specific gravity (expressed in degrees) may go above or 
below the yearly average by more than 10 per cent. 

The per cent, of fat may go above or below the yearly aver- 
age by more than 30 per cent. 

The per cent, of total solids may go above or below the year- 
ly average by more than 14 per cent. 

The per cent, of solids not fat may go above or below the 
yearly average by more than 10 per cent. 

To illustrate, if the average test of a herd during a whole 
period of lactation is 4.0 per cent., the test on a single day may 
exceed 4.0-t-rVo X 4.0=5.2, or may go below 2.8 per cent., (viz., 
4.0— x% X 4.0); if the average specific gravity is 1.031 (lacto- 
meter degrees, 31-) the specific gravity of the milk on a single 
day may vary between 1.0279 and 1.0341 (31 -f yVV X 31=34.1; 
31 -tVoX 31=27.9). 

170. Influence of heavy grain-feeding on the quality of 
milk. If cows are not starved or underfed, an increase 
in the feeding ration will not materially change the rich- 
ness of the milk produced, as has been shown by careful 

1 Book of the Dairy, p. 32. 

2 See page 94. 



144 Testing Milk and Its Products. 

feeding experiments conducted under a great variety of 
conditions and in many countries. Cows that are fairly 
well fed will almost invariably give more milk when 
their rations are increased, but the milk will remain of 
about the same quality after the first few days are passed 
as before this time, provided the cows are in good health 
and under normal conditions. Any change in the feed 
of cows will usually bring about an immediate change in 
the fat content of the milk, as a rule increasing it to some 
extent, but in the course of a few days, when the cows 
have become accustomed to their new feed, the fat content 
of the milk will again return to its normal amount. 

171. The records of the cows included in the feeding 
experiment at the Illinois station, to which reference has 
been made on p. 133, furnish illustrations as to the effect 
of heavy feeding on the quality of milk. The feed, as 
well as the milk of the cows, was weighed each day of 
the experiment. During the month of December each 
cow was fed a daily ration consisting of 10 lbs. of tim- 
othy hay, 20 lbs. of corn silage and 2 lbs. of oil meal; 
the table on p. 134 shows that cow ^o. 3 produced on 
this feed an average of 12.1 lbs. of milk, testing 3.8 per 
cent, of fat. In January the grain feed was gradually 
increased until the ration consisted of 12 lbs. of timothy 
hay, 8 lbs. of corn and cob meal, 4 lbs. of wheat bran and 
4 lbs. of oil meal. All the cows gained in milk on this 
feed; cow No. 3 thus gave an average of 4 lbs. more 
milk per day in January than in December, but the aver- 
age test of her milk was 3. 7 per cent., or one-tenth of one 
per cent, lower than during the preceding month. The 
heavy grain feeding was continued through February 



Testing Milk on the Farm. 145 

and March, when it reached 12 lbs. of timothy hay, 12 
lbs. of corn and cob meal, 6 lbs. of wheat bran and 6 lbs. 
of oil meal per day. The records show that the flow of 
milk kept up to 16 lbs. per day in February in case of 
this cow, but fell to 14 lbs. in March and April, the 
average test of the milk being, in February 3.6, in March 
3. 8, and in April 4. per cent. The milk was, therefore, 
somewhat richer in April than in December, but not 
more so than is found normally, owing to the progress of 
the period of lactation. 

172. Influence of pasture on the quality of milk. On 
May 1, the cows were given luxuriant pasture feed and 
no grain ; a slight increase in the average amount of milk 
produced per day followed, with a reduction in the test, 
this being 3.8 per cent., the same as in December. 

During all these changes of feed, there was, therefore, 
not much change in the richness of the milk, while the 
flow of milk was increased by the heavy grain feeding 
for several months, as well as by the change from grain- 
feeding in the barn to pasture feed with no grain. ^ 

173. The increase which has often been observed in the 
amount of butter produced by a cow, as a result of a 
change in feed, doubtless as a rule comes from the fact 
that more, but not richer milk is produced. The quality 
of milk which a cow produces is as natural to her as is 
the color of her hair and is not materially changed by 
any special system of normal feeding. ^ 

1 For further data on this point, see Cornell (N. Y.) exp. sta., bulletins 
13, 22, 36 and 49; N. D. exp. sta., bull. 16; Kansas exp. sta., report, 1888; 
Hoard's Dairyman, 1896, pp. 924-5. 

2 On this point numerous discussions have in recent years taken place 
in the agricultural press of this and foreign countries, and the subject bas 
been ^under debate at nearly every gathering of farmers where feeding 

1 



146 Testing Milk and Its Products. 

174. Method of improving the quality of milk. The qual- 
ity of the milk produced by a herd can generally be im- 
proved by selection and breeding, i. e., by disposing 
of the cows giving poor milk, say below 3 per cent, of 
fat, and by breeding to a pure- bred bull of a strain 
that is known to produce rich milk. This method can- 
not work wonders in a day, or even in a year, but it is 
the only certain way we have to improve the quality of 
the milk produced by our cows. 

It may be well in this connection to call attention to 
the fact that the quality of the milk which a cow pro- 
duces is only one side of the question; the quantity is 
another, and an equally important one. Much less dissat- 
isfaction and grumbling about low tests among patrons of 
creameries and cheese factories would arise if this fact 
was more generally kept in mind. A cow giving 3 per 
cent, milk should not be condemned because her milk 
does not test 5 per cent. ; she may give twice as much milk 

proble us have been considered. Many farmers are firm, in their belief 
that butter fat can be "fed into" the milk of a cow, and would take excep- 
tion to the conclusion drawn in the preceding. The results of careful in- 
vestigations by our best dairy authorities point conclusively, however, in 
the direction stated, and the evidence on this point is overwhelmingly 
against the opinion that the fat content of the milk can be materially and 
for any length of time increased by changes in the system of feeding. The 
most conclusive evidence in this line is perhaps the Danish co-operative 
cow-feeding experiments, conducted during the nineties with over 2,000 
cows in all. The conclusion arrived at by the director of the Copen- 
hagen experiment station, under whose supervision the experiments have 
been conducted, has been repeatedly stated in the published reports of the 
station: that the changes of feed made in the different lots of cows included 
in the experiments have had practically no influence on the chemical 
composition (the fat content) of the nilk produced. In these experiments 
grain feeds have been fed :i gainst roots, against oil cake, and against wheat 
bran or shorts; grain and oil cake have furthermore been fed against roots, 
and roots have been given as an additional feed to the standard rations 
tried,— ill all cases with practically negative results so far as changes in 
the fat contents of the milk produced are concerned. 



Testing Milk on the Farm. 147 

per day as a 5 per cent, cow, and will therefore produce 
considerably more butter fat. The point whether or not 
a cow is a persistent milker is also of primary import- 
ance; a production of 300 lbs. of butter fat during a 
whole period of lactation is a rather high dairy standard, 
but one reached by many herds, even as the average for 
all mature cows in the herd. It should be remembered 
that a high production of butter fat in the course of the 
whole period of lactation is of more importance than a 
very high test. 



CHAPTEE X. 
COMPOSITE SAMPLES OF MILK. 

175. Shortly after milk testing had been introduced to 
some extent in creameries and cheese factories^ it was 

suggested by Patrick, 
then of the Iowa ex- 
periment station, Hhat 
a great saving in labor 
without affecting the 
accuracy of the results 
could be obtained by 
mixing the daily sam- 
ples of milk from one 
source, and testing this 
mixture instead of 
each sample contribu- 
ting thereto. Such a 
mixture is called a 
composite sample. The 
usual methods of tak- 
ing such samples at 
FIG. 51. Taking test samples at in-take. creameries and cheese 

factories during the past few years have been as follows: 

176. Methods of taking composite samples, a. Use of 
tin dipper. Either pint or quart Mason fruit jars, or milk 
bottles provided with a cover, are used for receiving the 
daily samples. One of these jars is supplied for each 

1 Bulletin No. 9, May 1890. 




Composite Samples of Milk. 149 

patron of the factory and is labeled with his name or 
number. A small quantity of preservative (bi-chromate 
of potash, bi-chlorid of mercury, etc., see 188) is added 
to each jar; these are placed on shelves or somewhere 
within easy reach of the operator who inspects and 
weighs the milk as it is received at the factory. When 
all the milk delivered by a patron is poured into the 
weighing can and weighed, a small portion thereof, 
usually about an ounce, is put into the jar labeled with 
the name or number of the patron. The samples are 
conveniently taken by means of a small tin dipper hold- 
ing about an ouace. This sampling is continued for a 
week, ten days, or sometimes two weeks, a portion of 
each patron's milk being added to his particular jar 
every time he delivers milk. A test of these composite 
samples takes the place of separate daily tests and gives 
accurate information regarding the average quality of the 
milk delivered. by each patron during the period of 
sampling. The weight of butter fat which each patron 
brought to the factory in his milk during this time, is 
obtained by multiplying the total weight of milk deliv- 
ered during the sampling period by the test of the 
composite sample, dividing the product by 100. 

177. This method of taking composite samples has been 
proved to be practically correct. It is absolutely correct 
only when the same weight of milk is delivered daily by 
the patron. If this is not the case, the size of the various 
small samples should bear a definite relation to the milk 
delivered; one sixteen- hundredth, or one two-thousandth 
of the amount of milk furnished should, for instance, be 
taken for the composite sample from each lot of milk. 



150 Testing Milk and Its Products. 

This can easily be done by means of special sampling 
devices (see 179 et. seq. )• As the quantities of the milk 
delivered from day to day by each patron vary but little, 
perhaps not exceeding 10 per cent, of the milk delivered, 
the error introduced by taking a uniform sample, e. g. , 
an ounce of milk, each time is, however, too small to be 
worth considering in factory work, and the method of 
composite sampling described is generally adopted in 
separator creameries and cheese factories, where the 
payment of the milk is based on its quality. 

178. By this method of composite sampling each lot of 
rich, medium or thin milk receives due credit for the 
amount of butter fat which it contains, and errors that 
might arise from testing only one day's milk at irreg- 
ular intervals are avoided. In order to obtain reliable 
results by composite sampling it is essential that each 
lot of milk sampled shall be sweet and in good condition, 
containing no lumps of curdled milk or butter granules. 
The milk is of course always evenly mixed before the 
sample is taken. 

179. b. Drip sample. Composite samples are sometimes 
taken at creameries and cheese factories by collecting in 
a small dish the milk that drips through a fine hole or 
tube placed in the conductor spout through which the 
milk runs from the weighing can to the receiving vat or 
tank. A small portion of the drip collected each day is 
placed in the composite sample jar, or the quantity of 
drip is regulated so that all of it may be taken. In the 
latter case the quantity of milk delivered will enter into 
the composite sampling as well as its quality, and the 
sample from, say 200 lbs. of milk, will be twice as large 
as the sample from 100 lbs. of milk. 



Composite Samples of Milk. 151 

Where it is desiredto vary the size of the samples accord- 
ing to the quantity of milk delivered from day to day, it is 
necessary to adopt the method of collecting drip samples, 
just explained, or to make use of special sampling devices, 
like the ^'milk thief," the Scovell, or the Equity sampling 
tube. The principle of these tubes is the same, and it 
will be sufficient to describe here only the latter two. 

180. c. The Scovell sampling tube. This convenient 
device for sampling milk ^ (fig. 52) consists of a drawn 
copper or brass tube, one-half to one inch in 
diameter; it is open at both ends, the lower end 
sliding snugly in a cap provided with three 
elliptical openings at the side, through which the 
milk is admitted. The milk to be sampled is 
poured into a cylindrical pail, or the factory 
weighing can, and the tube, with the cap set so 
that the apertures are left open, is lowered into 
the milk until it touches the bottom of the can. 
The tube will be filled instantly to the level of 
the milk in the can and is then pushed down 
against the bottom of the can, thereby closing the 
.apertures of the cap and confining within the tube 
a column of milk representing exactly the quality 
of the milk in the can and forming an aliquot part 
thereof. The milk in the sampling tube is then 
emptied into the composite sample jar by turn- 
ing the tube upside down. yxg.. 52. 

181. If the diameter of the sampling pail used scoveii 

milk samp- 
is 8 inches, and that of the sampling tube ^ inch ung tube. 

(these dimensions will be found convenient in sampling 



1 Kentucky experiment station, 8tb report, pp. xxvi-xxxii. 



152 Testing Milk and Its Products. 

milk from single cows), then the quantity of milk 
secured in the tube will always stand in the ratio to that 
of the milk in the pail, of (J)^ to 8V that is, as 1 to 
256, no matter how much or how little milk there is in 
the pail, the sample will represent -^^^ part of the milk. 
For composite sampling of the milk of single cows, this 
proportion will prove about right; if more milk is wanted 
for a sub- sample, dip twice, or pour the milk to be 
sampled into a can of smaller diameter. If the mixed 
milk from a number of cows is to be sampled, a wider 
sampling can be used. By adjusting the diameters of 
the tube and the can, any desired proportion of milk can 
be obtained in the sample. 

For factory sampling, with a weighing can, 26 inches 
in diameter, a tube three-quarters of an inch in diameter 
will be found of proper dimensions. 

In using any one of these tubes, the size of the sample 
is regulated by the amount of milk in the sampling can, 
as the milk always rises to the same height in the tube 
as in the can. In all cases cylindrical sampling cans must 
be used. 

182. The sampling tube will furnish a correct sample 
of the milk in the can, even if this has been left standing 
for some time; it is better, however, to take out the sam- 
ple soon after the milk has been poured into the can, as 
the possible error of cream adhering to the sides of the 
sampling tube is then avoided. 

183. The accuracy of the sampling of milk by means 
of the Scovell tube was proved beyond dispute in the 

1 The contents of a cylinder are represented by the formula 7ri2h, r be- 
ing the radius of the cylinder, and h its height. The relation between two 
cylinders of the same height, the radii of which are R and r, is therefore 
as 7rR2h to TTrSh, or as R2 to r2. 



Composite Samples of Milk. 153 

breed tests conducted at the World's Columbian Exposi- 
tion in 1893j in which tests this method was adopted for 
sampling the milk produced by the single cows and the 
different herds. ^ The data obtained in these breed tests 
also furnish abundant proof of the accuracy of the Bab- 
c6ck test. 

184. d. The Equity milk sampler. This sampling device 
is the invention of Messrs. Joseph Kolarik and Carl 
Werder. A half inch brass tube, closed by a disc fastened 

to a rod within and kept in place by 

a spring at the top, is held in upright 

position inside of the weigh can by 

the guide piece clamped to the rim of 

the can. The operation is simple. The 

milk is poured into the weigh can, 

the tube is lifted until its bottom end r— |h_ 

is clear of the milk, a slight pressure / J ^ 

of the finger at the top opens the tube, ' 

Fig. 53. * ^ ^ ' Fig. 54. 

Takingthe and SO Opened it is let down through Discharging 

sample. ^^^ ^^y^^ closiug of itself as it touches IntS'far. 
the bottom of the can. The sample of milk is now in 
the tube and cannot leak out or be lost. The com- 
posite sample bottle is held under the spout and the 
tube raised as high as the guide will permit. The 
construction of this guide is such ,that the tube, when 
raised to its level, discharges, automatically, into the test 
jar through the spout (see figs. 53 and 54). 

185. e. Composite sampling with a "one-third sample 
pipette." Milk is sometimes sampled directly from the 

1 Kentucliy experiment station, 8th report, pp. xxx-xxxi. Another 
form of a milk sampling tube in use at the Iowa experiment station was 
described and iUustrated by Mr. Eckles in Breeder's Gazette, May 19, 1897 




■iiniinjiir 



154 Testing Milk and Its Products. 

weighing can into the Babcock test bottle by means of a 
pipette holding 5.87 cc, which is one-third the size of 
the regular pipette. This quantity is measured into the 
test bottle from three successive lots of milk from the 
same patron and the test then made in the ordinary 
manner. In this way one test shows the average com- 
position of the milk delivered during three successive 
days or deliveries. When this method is adopted, as 
many test bottles are provided as there are patrons; 
there is no need of using 
any preservatives for the 
milk in this case. Fig. 
55 shows a convenient 
rack for holding the test 
bottles used in compos- 
ite sampling with a ' 'one- 
third sample pipette. ' ' 

Accurate results can be 
obtained by this method 
of sampling, if care is 
taken in measuring out 
the milk, and if it is not 
frozen or contains lumps 
of cream. It is doubtful if the method has any advan- 
tage over the usual method of composite sampling. If 
milk is delivered daily and each lot is sampled with the 
one-third pipette, twice or three times the number of tests 
are required as when composite samples are taken in jars 
and tested once every week or ten days. This method 
furthermore takes a little more time in the daily sampl- 
ing than the other, as the quantity of milk must be meas- 



mjm 



liiiiinin 



»mj»if|«^ilM 



■IIUBSlll 



Fig. 55. Test-bottle rack for use in 
creameries and cheese factories. 



Composite Samples of Milk. 155 

ured out accurately each time. If the test bottle is acci- 
dently broken or some milk spilled, the opportunity of 
ascertaining the fat content of the milk delivered during 
the three days is lost 5 if a similar accident should occur 
in testing composite samples collected in jars, another 
test can readily be made. 

186. Accuracy of the described methods of sampling. 
An experiment made at the Wisconsin Dairy School may 
here be cited, showing that concordant results will be 
obtained by the use of the drip sampling method and the 
Scovell tube. Two composite samples were taken from 
fifty different lots of milk, amounting to about 6,000 flbs. 
in the aggregate. One sample was taken of the drip 
from a hole in the conductor spout through which the 
milk passed from the weighing can 5 the other was taken 
from the weighing can by means of a Scovell sampling 
tube. The following percentages of fat were found in 
each of these samples: ^ 



Drip composite sample 

Scovell tube composite sample. 



Bahcock test. 



4.0 per cent. 
4.0 per cent. 



Qravimetric 
analysis. 



4.04 percent. 
4.06 percent. 



Preservatives foic Composite Samples. 
187. When milk is kept any length of time under ordi- 
nary conditions, it will soon turn sour and become lop- 
pered, and further decomposition shortly sets in, which 
renders the sampling of the milk both difficult and unsatis- 
factory (19). The changes which occur when milk sours 
are due to the formation of lactic acid by the action of 
bacteria on milk sugar; the acid coagulates the casein of the 

1 See also 189 et seq. 



156 Testing Milk and Its Products. 

milk, but does not destroy or attack the butter fat (32). 
The period during which milk will remain in an appar- 
ently sweet or fresh condition varies with the temperature 
at which it is kept, and with the cleanliness of the milk. 
It will not generally remain sweet longer than two days at 
the outside, at ordinary summer or room temperature. 

In order to preserve composite samples of milk in a 
proper condition for testing, some chemical which will 
check or prevent the fermentation of the milk must be 
added to it. A number of substances have been proposed 
for this purpose. 

188. Bi-chromate of potash. This preservative is, in 
the opinion of the authors, to be preferred, on account of 
its relative harmlessness, its cheapness and efficiency. 
The bichromate method for preserving samples of milk 
was proposed by Mr. J. A. Alen, city chemist of Gothen- 
burg, Sweden, in 1892,^ and has been generally adopted 
in dairy regions in this country and abroad. While not 
perfectly harmless, the bi-chromate is not a violent poison 
like other chemicals proposed for this purpose, and no 
accidents are liable to result from its use; at least none 
have been known to the writers to occur during the years 
that it has been used in creameries or dairies as a pre- 
serving agent. 

189. The quantity of bi-chromate necessary for preserv- 
ing half a pint to a pint of milk for a period of one or 
two weeks is about one-half gram (nearly 8 grains). As 
there are about 900 half- grams in a pound, this quantity 
will suffice for nine weeks in a creamery having one 
hundred patrons, if tests are made once a week, or for 
three months (90 days) if tests are made every ten days. 

1 Biedermann's Centralblatt, 1892, p. 549. 



Composite Sample of Milk. 157 

According to Winton and Ogden/ a .22-inch pistol 
cartridge shell cut to ^ inch long, or a .32-inch calibre 
shell cut to J inch long, when loosely filled, will hold 
enough powdered bi chromate to preserve \ pint, and a 
.32-inch calibre shell cut to J inch long will hold enough 
to preserve one pint. These shells may be conveniently 
handled by soldering to them a piece of stiff wire which 
serves as a handle. The amount of bichromate placed 
in each composite sample jar would fill about half the 
space representing one per cent, in the neck of a Bab- 
cock milk test bottle. 

190. The first portions of milk added to the composite 
samplejars containing the specified amount of bi-chro- 
mate will be colored almost red, but as more milk is 
added, day by day, its color will become lighter yellow. 
The complete sample should have a light straw color; 
such samples are most easily mixed with acid when 
tested. If more bi- chromate is used, the solution of 
the casein in the acid is rendered difficult and requires 
persistent shaking. Bi- chromate can be bought at drug 
stores or from dairy supply dealers at about 30 cents a 
pound and will cost about 25 cents a pound at wholesale. 
Powdered bi- chromate of potash should be ordered, and 
not crystals, as the latter dissolve only slowly in the 
milk. Farrington's bi-chromate tablets contain the cor- 
rect quantity of preservative for a quart sample, and will 
be found convenient. 

191. Other preservatives for composite samples. Among 
other substances recommended for use in butter or cheese 
factories as milk preservatives for composite samples are 

1 Connecticut experiment station, report for 1884, p. 222. 



158 Testing Milk and Its Froducts. 

formalin, boracic-acid compounds, chloroform, carbon 
bi-sulfid,^ copper ammonium sulfate, sodium fluorid, 
ammonia glycerin (sp. gr., 1.031), and mixtures contain- 
ing mercuric chlorid (corrosive sublimate) with anilin 
color (rosanilin).^ The coloring matter in the latter 
compounds is added to give a rose color to the sample 
preserved, thus showing that the milk is not fit for con- 
sumption; the bi-chromate giving naturally a yellow color 
to the milk, renders unnecessary the addition of any 
special coloring matter. 

None of the substances mentioned are as cheap as bi- 
chromate or more effective for factory purposes when the 
milk is to be kept not to exceed two or three weeks. The 
compounds containing corrosive sublimate are violent poi- 
sons and must always be handled with the greatest care, 
lest they get into the hands of children or persons unfamil- 
iar with their poisonous properties; they will preserve the 
milk longer than bichromate when applied in sufficient 
quantities, but for factory use the latter is amply effective 
and has, as already stated, the advantage in several 
respects. During late years corrosive sublimate tablets 
have, however, come into general use in factories. 

192. Care of composite samples. The composite sam- 
ple jars should be kept covered to prevent loss by evapor- 
ation, and in a cool, dark place, or at least out of direct sun- 
light; the chromic acid formed by the reducing influence 
of light on chromate solutions produces a leathery cream 
which is very difficultly dissolved in sulfuric acid. 



1 Delaware experiment station, eighth report, 1896, which also see for 
trials with a large number of diflferent preservatives. 

2 Iowa experiment station, bulletins 9, 11, 32. 



Oomposite Sample of Milk. 159 

A coatiDg of white shellac has been suggested to protect 
the labels of the composite sample jars. The shellac is ap- 
plied after the names of the patrons have been written on 
the labels, and when these have been put on the jars. 
Gummed labels, lx2|^ inches, answer this purpose well. 

In keeping the milk from day to day, care should be 
taken that the cream forming on the milk does not stick 
to the sides of the jars in patches above the level of the 
milk. Unless the daily handling of the jars and the 
addition of fresh portions of milk be done with sufficient 
care, the cream will become lumpy and will dry on the 
sides of the jars. In some cases it is nearly impossible 
to evenly distribute this dried cream through the entire 
sample so as to make the composite sample a true repre- 
sentative of the different lots of milk from which it has 
been taken. 

193. Every time a new portion of milk is added to the 
jar this should be given a gentle horizontal rotary mo- 
tion, thereby mixing the cream already formed in the 
jar with the milk and rinsing off the cream sticking to 
its side. This manipulation also prevents the surface of 
the milk from becoming covered with a layer of partially 
dried leathery cream. 

Composite samples having patches of dried cream on 
the inside of the jar are the result of carelessness or ignor- 
ance on the part of the operator. If proper attention is 
given to the daily handling of the composite samples, the 
cream formed in the jars can without difficulty again be 
evenly mixed with the milk. 

194. Fallacy of averaging percentages. A composite 
sample of milk should represent the average quality of 



160 



Testing Milk and Its Products. 



the various lots of milk of which it is made up. This 
will invariably be true if a definite aliquot portion or 
fraction of the different lots of milk is taken. If the 
weights of, say ten different lots of milk, are added to- 
gether and the sum divided by ten, the quotient will 
represent the average weight per lot of milk, but an 
average of the tests of the different lots obtained in this 
way may not be the correct average test of the entire 
quantity of milk. The accuracy of sach an average 
figure will depend on the uniformity in the composition 
and weights of the ten lots of milk. When there is no 
uniformity, the weights of the different lots of milk as 
well as their tests must be considered. The following 
example illustrates the difference between the arithmet- 
ical average of a number of single tests and the true 
average test of the various lots. 

Methods of calculating average percentages. 



I. Milk varying in weights and tests. 


II. Milk of uniform weights and tests. 


Lot. 








Lot. 


ad 


fa 




I 


fts. 

120 

570 

360 

55 

82 


per ct. 

3.5 
5.0 
5.2 
30 
4.0 


fts. 

4.2 

28.5 

18.7 

1.6 

3.2 


I 


lbs. 

250 
225 
240 
238 
234 


per ct. 

4.2 
4.0 
4.3 
4.1 

4.4 


lbs. 
10.5 


II 


II 


90 


III 


Ill 


10 3 


IV 


IV 


9.7 


V 


V 


10.3 




Total 

Average 

True average 

test 




Total 


1187 
237 




56.2 
11.24 


1187 
237 




49.8 


Average.... 

Trueaver'ge 
test 


4.14 
4.731 


4.20 
4.222 


10.0 















156.2X100 
1187 



=4.73. 



9.8X100 
1187 ' 



Composite Samples of Milk. 161 

195. The figures given in the table show that when 
the different lots of milk vary in test and weight, as in 
the first case, the correct average test of the 1187 lbs. of 
milk is not found by dividing the sum of these tests by 
five, which would give 4. 14 per cent. ; but the percentage 
which 56.2 (the total amount of fat in the mixed milk) 
Is of 1187 (the total amount of milk), is 4.73, and this 
is the correct average test of the mixed milk made up 
of the five different lots. 

In the second case, the variations in both the weights 
of the different lots of milk and their tests, are compara- 
tively small, and both methods of calculation give there- 
fore practically the same average test; but also in this 
case, the correct average test is found by dividing the 
total amount of fat by the total quantity of milk, making 
4.22 per cent., instead of 4.20 per cent., which is the 
arithmetical mean of the five tests. The quantities of 
milk in the various lots do not enter into the calculation 
of the latter. ^ 

196. The second example represents more nearly than 
the first one the actual conditions met with at creameries 
and cheese factories. As a rule the mixed milk from a 
herd of cows does not vary more in total weight or tests, 
within a short period of time like one to two weeks, than 
the figures given in this example. On account of this 
fact, samples taken, for instance, with a small dipper may 
give perfectly satisfactory results to all parties concerned. 
If the different lots of milk varied in weight and test from 



1 In the experiment given on p. 137, ttie arithmetical mean of the tests 
given is 5.15 per cent., while the true average fat content of the milk is 4.85 
per cent. 

11 



162 Testing Milk and Its Products. 

day to day, as shown in the first case, it would be neces- 
sary to use a '* milk thief" or one of the sampling tubes 
for taking the composite samples 5 the size of each of the 
samples taken would then represent an exact aliquot por- 
tion of the various lots of milk (180). 

197, A patron's dilemma. The following incident will further 
explain the difficulties met with in calculating the average tests 
of different lots of milk. 

The weekly composite sample of the milk supplied by a 
creamery patron from his herd of 21 cows tested 4.0 per cent. fat. 
One day the farmer brought to the creamery a sample of the 
morning's milk from each of his cows, and had them tested; after 
adding the tests together and dividing the sum by 21, he obtained 
an average figure of 5. 1 per cent, of fat. From' this he concluded 
that the average test of the milk from his cows ought to be 5.1, 
instead of 4.0, and naturally asked for an explanation. 

198. The first thing done was to show him that while 5.1 was 
the correct average of the figures representing the tests of his 
twenty-one cows, it was not a correct average test of the mixed 
milk of all his cows, as he had not considered, in calculating 
this average, the quantities of milk yielded by each cow; the 
following illustration was used: 

Cow No. 1, yield 25 ft)S. of milk, test 3.6 per cent.=0,9 fts. of butter fat. 
Cow No. 2, yield 6 fts. of milk, test 5.0 per cent. =0.3 lbs. of butter fat. 

Total 31 K)S. 2^8.6 12 fts. 

4.3 per cent. 

The two cows gave 31 lbs. of milk containing 1.2 lbs. of fat; 
the test of the mixed milk would therefore not be 4.3 per cent. 

(^^^±^), but ^^^1^=3.87 per cent. If the fat in the mixed 

milk was calculated by the average figure 4.3 per cent., 1.33 lbs. 
of fat would be obtained, i. e., 0.13 lbs. more than the cows 
produced. 

In order to further demonstrate the actual composition of 
the mixed milk of the twenty-one cows, the milk of each cow 
was weighed and tested at each of the two milkings of one day. 
The weights and tests showed that the cows produced the fol- 
lowing total number of pounds of milk and of fat: 



Composite Samples of Milk. 



163 



Morning milking, 113.3 lbs. of milk, containing 5.17 lbs. of fat. 
Night milking, 130.9 lbs. of milk, containing 4.98 lbs. of fat. 

5 17 X 100 

The morning milk therefore contained ' ^^gg = 4.56 per 

4 98 X 1 00 

cent, of fat, and the night milk " 1309 =^3.80 per cent, of fat. 

The sum of the morning and night milkings gave: milk, 
244.2 lbs., fat 10.15 lbs. The mixed morning and night milk, 

therefore, contained '^^^^^ — =4.1 per cent, of fat. This is the 

true average test of the morning and night milkings of these 
twenty-one cows, as found by weighing and testing separately 
the milk of each cow at both milkings. 

199. The total milk was strained into a large can at the farm, 
both in the morning and in the evening. A sample of the 
mixed milk was in each case taken with a long-handled dipper 
as soon as the milkings were finished. When the cans of milk 
were delivered at the creamery, a sample of each was taken 
with a Scovell sampling tube. The tests of these four samples 
are given below, together with the results from the individual 
tests: 



Sample taken at the farm, with 
dipper 

Sample taken at creamery with Sco- 
vell tube 

Calculated from weights and tests of 
milk from each cow 



Morning Milk 



4.4 per ct. 
4.6 '* 

4.5 ♦' 



Night Milk. 



3.8 per ct. 

3.7 " 

3.8 ♦* 



The figures given show that practically uniform tests were 
obtained by the different methods of sampling. 

The sum of the weights of the milk from the different cows 
was as follows: 





Morning Milk. 


Night Milk. 


Daily Milk. 


Total milk produced 

Milk in samples 


113.3 lbs. 

12.3 lbs. 

2.5 lbs. 


130.9 lbs. 
8.9 lbs. 


244.2 lbs. 
21.2 lbs. 


Milk for family use 


2.5 lbs. 








Milk taken to creamery 


98.5 lbs. 


122.0 lbs. 


220.5 lbs. 



164 Testing Milk and Its Products. 

It has already been shown from the weights and tests of each 
cow's milk that the herd milk contained 4.1 percent, of fat. 
Multiplying the total milk delivered at the creamery, 220.5 lbs., 
by .041 gives 9.04 K)s. of fat. The morning and night milkings, 
which were weighed and tested separately, contained the fol- 
lowing quantities of butter fat: 

Morning Milk 98.5 R)s.X.045=4.43 fbs. of butter fat 

Night Milk 122.0 lbs. X. 038 =4. 63 R)s. of butter fat 

Total 220.5 R)s. 9.06 lbs. 

By weighing, sampling and testing separately the morning 
and night milkings of twenty-one cows, deducting the weight 
of milk in the samples and what was taken out for family use, 
it was found that 9.04 lbs. of butter fat was sent to the creamery. 
The weights and tests of this same milk when delivered at the 
creamery, gave 9.06 lbs. of butter fat. 

200. This example furnishes an excellent illustration of the 
accuracy of the Babcock test and of the closeness of results which 
may be obtained at creameries when proper care is taken in 
weighing, sampling and testing the milk. Similar demonstra- 
tions may be made by any factory operator, and with equally 
satisfactory results, provided the work is carefully done. 



CHAPTEEXL 
CREAM TESriNQ AT CREAPIERIES. 

201. The cream delivered at gathered- cream factories 
is now in many localities tested by the Babcock test, and 
this has been adopted as a basis of paying for the cream 
in the same manner as milk is paid for at separator 
creameries. It has been found to be more satisfactory to 
both cream buyer and seller, than either the oil- test churn 
or the space (or gauge) systems which have been used 
for this purpose in the past. 

The details of the application of the Babcock test to 
the practical work at cream-gathering creameries have 
been carefully investigated by Winton and Ogden in 
Connecticut/ Bartlett in Maine, ^ and Lindsey in Massa- 
chusetts,^ and we also owe to the labors of these chemists 
much information concerning the present workings of 
other systems of paying for the cream delivered at 
creameries. 

202. The space system. Numerous tests have shown 
that one space or gauge of cream does not contain a defi- 
nite, uniform amount of fat. In over 100 comparisons 
made by Winton it was found that one space of cream * 

1 Conn, experiment station (New Haven), bull. No, 108 and 119 ; report 
1894, pp. 214-244. 

2 Maine experiment station, bull. 3 and 4 (S. S.). 

3 Hatch experiment station, report 1894, pp. 92-103 ; 1895, pp. 67-70. 

4 The space is the volume of a cylinder, 83^ inches in diameter and ^| of 
an inch high. The number of spaces in each can of milk is read off before 
skimming by means of a scale marked on a strip of glass in the side of the 
can (Conn. exp. sta., bull. No 119). 



166 



Testing Milk and Its Products. 



contained from .072 to .170 Sbs. of butter fat, or on the 
average .13^1b., and the number of spaces required to 
make one pound of butter varied from 5.01 to 11.72. It 
is also claimed that in the winter season when the cream 
is gathered at long intervals, like once a week, it is neces- 
sary for the buyer to accept the seller^ s statement of the 
record of the number of cream spaces which he furnishes. 




Fig. 56. The oil- test churn. 

since the cream cannot be left in the creaming cans for 
so long a time. These objections to the space system 
apply only to the method of paying for the cream, and 
not to the manner in which the cream is obtained. 

203. The oil-test churn. As stated in the introduction, 
the oiliest churn (fig. 56) has been used quite extensively 
among gather ed-cream factories; this system is based on 



Cream Testing at Creameries. 



167 



the number of creamery inches of cream which the 
various patrons deliver to the factory; one inch of cream 
contains 113 cubic inches.^ The driver pours the patron's 
cream into his 12-inch gathering pail, measures it with 
his rule and records the depth of the cream in the can, 
in inches and tenths of an inch. The cream is then stirred 
thoroughly with a ladle or a stout dipper, and a sample 
is taken by filling a test tube from the sample case, to the 
graduation mark by means of a small conical dipper pro- 
vided with a lip. A driver's case contains either two or 
three ^'cards," holding fifteen test tubes each (see fig. 57). 
The tubes as filled are 
placed in the case and 
the corresponding num- 
ber is in each instance 
recorded in front of the 
patron's name together 
with the number of 
inches of cream fur- 
nished by him. 

On the arrival at the 

,, ,. - FJg.:57. Cream-gatherer's 

creamery the tin cards sampiejcase. 

holding the tubes are placed in a vessel filled with 
water of the temperature wanted for churning (say, 60° 
in summer and 65° to 70° in winter). When ready for 
churning they are placed in the oil-test churn, the cover 
of the churn put on, and the samples of cream churned 
to butter. On the completion of the churning, the 
cards are transferred to water of 175-190° Fahr., 

1 1, e., a layer of cream one inch deep in a 12-inch pail; two inches in 
an 8-inch pail contains 10J.531 cubic inches, two inches in an 8%-inch pail 
110.18 cubic inches, and two inches in an 8>^-inch pail 113 49 cubic inches. 




168 Testing Milk and Its Products. 

where they are left for at least ten miDutes to raelt the 
butter and ^^cook the butter milk Into a curd." The 
oil will now be seen mixed all through the mass. The 
test tubes are then warmed to churning temperature 
and churned again, by which process the curd is broken 
into fine particles, which, when the butter is re- melted, 
will settle to the bottom. The butter is melted after 
the second churning by placing the tubes in water at 
150-175° F., allowing them to remain therein for at 
least twenty minutes. Some samples must be churned 
three or four times before a good separation of oil is 
obtained. A clear separation of oil is often facilitated 
by adding a little sulfuric acid to the tubes. 

The length of the column of liquid butter fat is de- 
termined by means of a special rule for measuring the 
butter oil; this rule shows the number of pounds and 
tenths of a pound of butter which an inch of cream will 
make; the first tenth of a pound on the rule is divided 
into five equal parts, so that measurements may be made 
to two- hundredths of a pound. The melted fat is meas- 
ured with the rule, by raising the tin card holding the 
bottles, to about the height of the eye; the reading is 
recorded on the driver's tablet under Test per inch, oppo- 
site the number of the particular patron. The test per 
inch multiplied by the inches and tenths of an inch of 
cream supplied will give the butter yield in pounds, 
with which the patron will be credited on the books of 
the creamery. 

204. The objection to this system of ascertaining the 
quality of cream delivered by different patrons lies in 
the fact that it determines the churndble fat, and not the 



Cream Testing at Creameries. 169 

total fat of the cream; the amoiint of the former obtained 
depends on many conditions beyond the control of the 
patron, viz. , the consistency, acidity and temperature of 
the cream, the size of the churn or churning vessel, etc. 
The same reasons which caused the churn to be replaced 
by methods of determining the total fat of the milk, in 
the testing of cows among dairymen and breeders, have 
gradually brought about the abandonment of the oil test 
in creameries and the adoption of the Babcock test in 
its place. 

205. The Babcock test for cream. Both the space 
system and the oil-test churn used for estimating the 
quality of cream at creameries have now largely been 
replaced by the Babcock test in the more progressive 
creameries in this country, and composite samples of 
cream are collected and tested in a similar manner as 
is done with milk at separator creameries and cheese 
factories. 

A very satisfactory method of arrangements for work- 
ing the Babcock test, in use in many eastern creameries, 
is described by Winton and. Ogden in the Connecti( ut 
report previously referred to. The cream gatherer who 
collects the cream in large cream cans is supplied with 
a spring balance (1, see fig. 58), pail for sampling and 
weighing the cream (2), sampling tube (3), and collect- 
ing bottles (5). At each patron's farm he takes from 
his wagon the sampling pail and tube, the scales, and one 
small collecting bottle. He should find in the dairy of 
the patron the cans of perfectly sweet cream, kept at a 
temperature of 40° to 50° F., and protected from dirt and 
bad odors. Either sour or frozen cream must be rejected. 



170 



Testing Milk and Its Products. 




Fig. 58. Outfit for cream testing by the Babcock test at gathered- 
cream factories. 

The patron's number should be painted in some conspic- 
uous place near the cream cans in his dairy house. The 
gatherer hangs the scale on a hook near the cream to be 
collected; the scale should be so made that the hand of 
the dial will stand at zero when the empty pail is hung 



Testing Cream at Creameries. 171 

on it. The cream is then poured at least twice from one 
can to another in order to mix it thoroughly. ^ 

206. When properly mixed, the cream is poured into 
the weighing pail and is weighed and sampled. The 
authors give the following description of the cream sam- 
pling tube used, and directions for sampling and weigh- 
ing the cream. 

'^Sampling Tube.— Thia tube, devised by Mr. Ogden, is of 
stout brass, about 3V of an inch thick, and a few inches longer 
than the weighing pail which is used with it. On the upper 
end, a small brass stop-cock of the same bore is fastened. It 
should be nickel plated inside and out, to keep the metal 
smooth and free from corrosion. These tubes may be obtained 
from less than j\ to over ^ inch bore. The greater the diameter 
of the weighing pail, the wider should be the bore of the tube. 
For use with pails 8 inches in diameter, a f\ inch bore sampling 
tube will serve the purpose, but when the pail has a diameter 
of 9 or more inches, a tube with a bore of ^ inch or more should 
be used. It must be borne in mind that doubling the diameter 
of the pail, or of the sampling tube, increases its capacity 
fourfold. 

"The tube when not in use should be kept in an upright 
position to permit draining. 

^^ Sampling and Weighing. — Lower the sampling tube, cock 
end up, with the cock open, to the bottom of the weighing pail 
which holds the mixed cream. When it is filled raise it out of 
the liquid and allow it to drain for a few seconds. By this 
means the tube is rinsed with the cream to be sampled and any 

1 The necessity of care in mixing the cream is shown by the following 
illustration given by the authors referred to. 

Per cent of fat in cream which stood for 2U hours. 

Sample drawn 
Surface. Bottom. with sampling tube. 

Not mixed 28.00 5.00 19.25 

Poured once 23.75 22.00 22.50 

Poured twice 22.25 



172 Testing Milk and Its Products. 

traces of cream adhering to the tube from previous use are 
removed. With the cock still open, slowly lower the sampling 
tube to the bottom of the cream pail. After allowing a moment 
for the cream to rise in the tube to the same height as in the 
pail, close the cock and raise the sampler carefully out of the 
cream. As long as the cock is closed, the cream in the tube 
will not flow out, unless the tube is strongly jarred. Allow the 
cream adhering to the outside of the tube to drain off for a few 
seconds, then put the lower end into the 1 to 1 J oz. wide-mouth 
glass collecting bottle which bears the patron's number on its 
cork, and open the cork. The cream will then flow out of the 
sampler into the bottle, which is afterwards securely corked and 
put into the cream gatherer's case. Immediately weigh the 
cream in the cream pail to the quarter or half pound, as may 
be judged expedient, and record the weight. 

"If the patron has more than one pailful, repeat with each 
pailful the operation of sampling and weighing, putting all the 
samples in one and the same bottle. Weigh all cream collected 
in one and the same sam,pUng pail and draw a sample from 
each separate portion weighed.'''' 

207. After sampling and weighing each patron' s cream 
it is poured into the driver's large can, and the sample 
bottles are carried in a case to the creamery where the 
contents of each bottle is poured into the composite 
sample jar of the particular patron. The samples of 
cream in the small bottles, besides furnishing the means 
of testing the richness of the cream, give the creamery 
owner or manager an opportunity to inspect the flavor 
of each lot of cream, and the condition in which it has 
been kept by the various patrons. Potassium bi-chro- 
mate is placed in the composite sample jars, and these 
are cared for and tested in the same manner as composite 
samples of milk (192). 

208. The collecting bottles should be cleaned with 
cold, and afterwards with hot water, as soon as they are 



Testing Or earn at Creameries. 173 

emptied, and before a film of cream dries on them. 
When washed and dried, these bottles are placed in the 
cases, ready for the next collecting trip. There can 
be no confusion of bottles since the corks and not the 
bottles are marked with the numbers of the respective 
patrons. 

209. When this system of testing composite sam- 
ples is adopted, the patrons are paid for the number 
of pounds of butter fat contained in their cream, in ex- 
actly the same way as milk is paid for at separator 
creameries. It makes no difference how thick or how 
thin the cream may be, or how much skim milk is left 
in the cream when brought to the factory. Eighty 
pounds of cream containing 15 per cent, of fat is worth 
no more or less than 48 pounds of cream testing 25 per 
cent.; in either case 12 pounds of pure butter fat is 
delivered. This will make the same amount of butter 
in either case, viz., toward 14 lbs., and both patrons 
should therefore receive the same amount of money. 

There is a small difference in the value of the tW(3 lots 
of cream to the creamery owner or the butter maker, in 
favor of the richer cream, both because its smaller bulk 
makes the transportation and handling expenses lighter, 
and because slightly less butter fat will be lost in the 
butter milk, a smaller quantity of this being obtained 
from the richer cream. But it is doubtful if the dif- 
ferences thus occurring are of sufficient importance to 
be noticed under ordinary creamery conditions; the 
example selected presents an extreme case of variation 
in the fat content of cream. A trial of this system at 
five Connecticut creameries, supplied mostly with Cooley 



174 Testing Milk and Its Froducts. 

cream, by over 175 patrons, showed that the average 
composition of the cream from the different patrons 
varied only from 16.9 to 19.8 per cent, fat The cream 
of some patrons on certain days contained only 9.5 per 
cent, of fat, and other patrons at times had as high a 
test as 30 per cent., but these great differences largely 
disappeared when the average quality of the cream 
delivered during a period of time, like a month or more, 
was considered. 

210. Smaller differences in the composition of cream 
will, however, always occur, even if the same system of 
setting the milk, like the cold deep-setting process, is 
used and the water is kept at the same temperature at 
all times. This is due to differences in the composition 
of the milk and its creaming quality 5 whether largely 
from fresh cows or from late milkers; whether kept 
standing for a time before being set or submerged in 
the creamer immediately after milking and straining; 
diameter of creaming cans, etc. Bartlett statesVthat the 
percentage of fat in the cream from the same cows may 
be increased ten per cent, or more by keeping the water 
at 70° instead of at 40° F. The higher temperature will 
give the richer cream, but the separation will not be so 
complete, since a richer skim milk is obtained from the 
milk set at this temperature. Separator cream is not 
materially influenced by the conditions mentioned, as 
the separator can be regulated to deliver cream of nearly 
uniform richness from all kinds of sweet milk. 

211. At creameries where both milk and cream are de- 
livered, somewhat of an injustice is done to patrons de- 

1 Maine experiment station, bulletin No. 3 (8. S.). 



Testing Cream at Creameries. 175 

livering cream, by paying for the amounts of butter fat 
furnished by the different patrons. By multiplying the 
cream fat by 1.03 (or by 1.044^), the value of his pro- 
ducts to the creamery is taken into proper account, and 
justice is done to all parties concerned^ (238). 

iSee Spillman, Dairy and Creamery, Chicago, April 1, 1899. 

2 This subject is discussed in detail in the 17th annual report of Wis. 
experiment station, pp. bO-92; see also the 20th report of this Station, pp. 
130-31. 



OHAPTEE XII. 
CALCULATION OF BUTTER AND CHEESE YIELD. 

A. — Calculation of Yield of Butter. 

212. Butter-fat test and yield of butter. The Babcock 
test shows the amount of pure butter fat contained in a 
sample of milk or other dairy products. The butter ob- 
tained by churning cream or milk contains, in addition 
to pure butter fat, a certain amount of water, salt and 
curd. While an accurate milk test gives the total quan- 
tity of butter fat found in the sample of milk or cream 
tested, the charn cannot be depended upon either to 
leave the same amount of butter fat in the butter milk or 
to include the same amount of water, salt and curd in the 
butter at each churning. 

If a quantity of milk, say 3,000 libs., be thoroughly 
mixed in a vat, and then divided into half a dozen equal 
portions, a Babcock test of the different lots will show 
the same percentage of butter fat in each portion. If, on 
the other hand, each of these lots be skimmed, and the 
cream ripened in different vats and churned separately, 
the same weight of butter from each lot of 500 lbs. of 
milk will not be obtained, even by the most expert but- 
ter maker, or if all the operations of skimming^ cream 
ripening, churning, salting and butter- working were 
made as nearly uniform as possible. Careful operators 



Calculation of Butter- and Cheese Yield. 



177 



can handle the milk and cream so that very nearly the 
same proportion of the fat contained in the milk is re- 
covered in the butter in different churnings, but since the 
water and salt in butter are held mechanically and are 
not chemically combined with it, the amounts retained 
by the butter are quite variable in different churnings, 
especially since the laws governing the retention of water 
in butter are but imperfectly understood. 

213. Variations in the composition of butter. As an 
illustration of the variability of butter in its composition, 
the analyses made in the breed tests at the World's Fair 
in 1893 may here be cited; the butter was in all cases 
made by as nearly identical methods and under as uni- 
form conditions as could possibly be obtained by the 
skilled operators having this work in charge: the aver- 
age composition of 350 samples of this butter, with upper 
and lower limits, was as shown in the following table: 

Composition of samples of butter, WorMs Fair, 189S. 



Average of 350 
analyses 

Lower and upper 
limits 



Water. 



Per cent. 

11.57 

8.63-15 00 



Fat. 



Per cent. 

81.70 

76.53-88.26 



Curd. 



Per cent. 

.95 

.50-2.14 



Salt and 
ash. 



Per cent. 

2.78 
1.01-8.58 



Sum of 

water,c'rd, 

salt and 

ash. 



Per cent. 
15.30 



Analyses of fifty samples of creamery butter taken in 
1896, from the tubs ready for market at as many Wiscon- 
sin creameries, showed that no two of them were ex- 
actly alike in composition, but varied within the limits 
given below: ^ 

1 Wisconsin experiment station, bull. 56. 
12 



178 Testing Milk and Its Products. 

Summary of analyses of Wisconsin creamery butter. 



Highest.. 
Lowest... 
Average. 



Water. 



Per cent. 

17.03 
9.18 
12.77 



Fat. 



Per cent. 

87.50 
11. Ql 



Curd. 



Per cent. 

2.45 
.36 

1.28 



Salt and 
ash. 



Per cent. 

4 73 
1.30 

2.87 



Sum of 

water, curd, 

salt and 



Per cent 

22.95 
12.50 

16.92 



The preceding analyses show the composition of butter 
made at one place where every possible effort was taken 
to produce a uniform product, and of butter made at 
fifty different creameries, where there was more or less 
variation in the different operations of manufacture and 
in the appliances and machinery used. The majority of 
the samples of butter analyzed, in either case, were very 
near the average composition given, but since there are 
such wide variations in the composition of the butter 
made by the uniform methods adopted in the World's 
Fair breed tests, butter of a more uniform composition 
cannot be expected from the thousands of different cream- 
eries and private dairies which supply the general market 
with butter. 

The analyses of the fifty samples of creamery butter, 
given above, show that the content of the butter fat 
varied from 77 to over 87.5 per cent., and according to 
the average of the analyses, 83 pounds of butter fat was 
contained in, or made, 100 lbs. of butter. There was, 
therefore, in this case produced 20.5 per cent, more 
butter than there was butter fat, since 

83 : 100 : : 100 : x; therefore 
100 X 100 



x = 



83 



= 120.5. 



Calculation of Butter- and Cheese Yield. 179 

214. ** Overrun " of churn over test. The yield of 
butter is not, however, as a rule compared with the 
amount of butter fat contained in the butter, but with 
the total butter fat of the whole milk from which it was 
made. This ^'increase of the churn over the test" is 
what is generally called overrun in creameries. 

The overrun obtained in different creameries, or even 
in the same creameries at different times, will be found 
to vary considerably. When the milk is accurately 
tested and the buttfer well worked, this overrun will vary 
from 10 to 16 per cent. ; that is, if a quantity of milk 
contains exactly 100 lbs. of butter fat, as found by the 
Babcock test or any other accurate method of milk test- 
ing, from 110 to 116 lbs. of butter ready for market may 
be made from it. 

215. Factors influencing the overrun. Even under the 
very best of care and attention to details, variations will 
occur in the speed of the separator, in the conduct of the 
ripening and churning processes, and in the condition of 
the butter when the churn is stopped; hence absolutely 
uniform losses of fat in skim milk and butter milk, or 
the same water- and salt contents of the butter, cannot 
be expected. 

The overrun is influenced by two factors: the losses of 
butter fat sustained in separating the milk and churning 
the cream, and the gain due to the admixture of water, 
salt, etc., in the manufacture of butter. Considering 
first the losses of fat in skim milk and butter milk, the 
separator will usually, when run at normal speed and 
capacity, leave the same per cent, of fat in skim milk, 
whether rich or poor milk is skimmed. An exception 



180 Testing Milk and Its Products. 

to this may be found in separating rich milk having 
large fat globules or milk from fresh milkers, in either 
of which cases the large size of the fat globules occasions 
a more complete separation of fat by the centrifugal 
force. But generally speaking, the statement holds good 
that the total loss of fat in separator skim milk is a factor 
of the quantity of milk run through the separator, rather 
than of its quality. It follows from this, however, that 
the relative losses of fat in skim milk will vary to some 
extent according to the quality of the milk separated. 
Selecting two extremes in the quality of milk, 2.5 and 
6.0 per cent, of fat, there will be found, say .2 per cent, 
of fat in the skim milk from either lot, provided the sep- 
arator is not unduly crowded, and the separation is con- 
ducted under normal conditions in each case. But .2 
per cent, fat makes 8 per cent, of the total fat in the poor 

milk (-^-—^ — =8), and only 8 per cent, of that in the rich 
milk. It takes 4000 lbs. of the 2.5 per cent, milk to 
furnish 100 lbs. of fat, and only 1666 lbs. of the 6 per 
cent, milk; in skimming the poor milk, a loss of .2 per 
cent, of fat is sustained in the skim milk from 4000 lbs. 
of milk, while in the rich milk a similar loss is sustained 
in the skim milk from only 1666 lbs. of milk. 

The example gives an extreme case, and one not likely 
to be met with in practice. The range in the richness of 
the milk delivered by different patrons at the factory is 
usually within one-half or one per cent of fat. In such 
cases the proportion of fat lost in skimming does not vary 
much, e. g., in case of milk containing 3.5 and 4.0 per 
cent, of fat, and variations in the overrun occurring when 
the proper care in skimming, ripening and churning is 



Calculation of Butter- and Cheese Yield, 



181 



taken, are due, therefore, primarily to differences in the 
water- and salt contents of the butter made (205). 

216. The losses from very poor, very rich and average 
milk, as received at creameries and cheese factories, can 
be traced from the following statement; this gives the 
quantities of fat lost in handling milk of four grades, 
viz: 2.5, 3.5, 4.0 and 6.0 per cent., in case of each grade 
calculated to a standard of 100 lbs. of fat in the milk. 

To supply 100 lbs. of fat would require the following 
amounts of the different grades of milk: 
4000 K)s. of milk testing 2.5 per cent, will contain 100 lbs. of fat. 
2857 " " " 3.5 " •' " 100 " " 

2500 " " " 4.0 " " " 100 '' " 

1666 " " " 6.0 " " " 100 " " 

Assuming that the skim milk contains .2 per cent, of 
fat and makes up 85 per cent, of the whole milk, that the 
butter milk test .3 per cent,, and forms 10 per cent, of 
the whole milk, the butter- fat record of the quantities of 
different grades of milk containing 100 lbs. of fat will 
appear as follows: 

Fat available for butter in different grades of milk. 



Grade of milk. 


Whole 
milk. 


Skim mnk. 


Butter 
milk. 


Total 

loss. 


Fat 
aval la 
ble for- 
butter. 


2.5 per cent 


4000 ft). 
2. 5 per ct. 


3400 ft). 
. 2 per ct. 


400 ft). 
.3perct. 


ft)S. 

80 

5.8 
5.0 


Percent. 


Fat 

3.5 per cent 


100 ft). 

2857 ft). 
3.5 per ct. 


6.8 ft). 

2^29 ft). 
.2 per ct. 


1.2 ft). 

286 ft). 
.3per ct. 


92.0 






Fat 


100 ft). 

2500 ft). 
4 per ct. 


4.9 ft). 

2125 ft). 
.2 per ct. 


.9 ft). 

250 ft). 
.3 per ct. 


94 2 


4.0 per cent 








Fat 

6.0 per cent 


100 ft). 

1666% ft). 
6 per ct. 


4.3 ft). 

1417 ft). 
.2 per ct. 


.7 ft) 

167 ft). 
.3 per ct. 


95.0 




1 


Fat 


100 ft). 


2.8 ft). 


.5 ft). 


3.3 


96.7 



182 Testing Milk and Its Products. 

The table shows that with 2.5 per cent. -milk, there is 
a loss of 6.8 lbs. of fat in the skim milk and 1.2 lbs. of 
fat in the butter milk for every 100 lbs. of fat in the 
whole milk, or a total loss of 8.0 lbs. from these sources. 
In case of 6 per cent, milk these losses are 2. 8 lbs. and 
.5 lbs. for skim milk and butter milk, respectively; a 
total loss of 3. 8 lbs. , or 4. 7 lbs. less than the losses with 
the very poor milk. This difference in the losses shrinks 
to only .8 pound of fat in case of 3.5 and 4.0 per ct. -milk, 
when a quantity containing 100 lbs. of fat is handled in 
both cases. 

The overrun from each of the four grades of milk can 
be calculated for butter containing a certain per cent, of 
fat. Assuming the fat content of butter to be 83 per cent. , 
on the average (213), the quantity of butter obtained 
from the 100 lbs. of fat, or rather from the portion 
thereof which is available for butter, in each case will be 
as follows: 

Butter cont. 
Available fat. 83pr.ct.fat. 

100 R)s. of fat from 4000 fts. of 2.5 pr. ct. milk, 92.0 lbs. = 110.8 lbs. 

100 " " " 2857 " 3.5 " " 94.2 " = 113.5 " 

100 " " " 2500 " 4.0 " " 95.0 " = 114.5 " 

100 " " " 1666 " 6.0 " " 96.7 " = 116.5 " 

The overrun in each case will be: 

For 2.5 per cent. milk=110.8-100=10.8 per cent. 
" 3.5 " " =113.5-100=13.5 " 

" 4.0 " " =114.5-100=14.5 . " 

" 6.0 " " =116.5-100=16.5 " . 

All butter makers should obtain more butter from a 
certain quantity of milk than the Babcock test shows it 
to contain butter fat, but it is impossible to know exactly, 
except by~chemical analysis, how much butter fat is lost 



Calculation of Butter- and Cheese Jield. 183 

in the skim milk and the butter milk, and how much 
water, salt and curd the butter will contain. 

217. Calculation of overrun. The overrun is calculated 
by subtracting the amount of butter fat contained in a 
certain quantity of milk, from the amount of butter made 
from it, and finding the per cent, which this difference is 
of the amount of butter fat in the milk. 

Example: 8000 Itjs. of milk is received at the creamery on a 
certain day; the average test of the milk is 3.8 per cent.; 340 R)s. 
of butter was made from this milk, as shown by the weights of 
the packed tubs. By a simple multiplication we find that the 
milk contained 8000 X. 038 =304 lbs. of butter fat. The difference 
between the weight of butter and butter fat is, therefore, 36 lbs. ; 

36 is ^^1^=11.8 per cent, of the quantity of butter fat in 

the milk; that is, the overrun for the day considered was 11.8 
per cent. 

The formula for the overrun is as follows: 

^T-_ (b— f) 100 
X- J 

h and/ designating the quantities of butter and butter 
fat, respectively, made from or contained in a certain 
quantity of milk. In the preceding example, the calcu- 
lation would be as follows: ^^^^!^=||^^'^=11.8 per cent. 

In gathered- cream factories the overrun will naturally 
come higher than in separator creameries, since no loss 
of butter fat in the skim milk occurs in the former. The 
overrun based on the amount of fat in the cream will not 
under average creamery conditions be likely to vary 
much from 18 per cent. 

218. Conversion factor for butter fat. A committee of 
the Association of American Agricultural Colleges and 
Experiment Stations at the ninth annual convention of 



184 Testing Milk and Its Products. 

the Association reported that ^' in the ninety- day Colum- 
bian Dairy Test, 96. 67 per cent, of the fat in the whole 
milk was recovered in the butter. This butter on the 
average contained 82.37 per cent, butter fat; in other 
words, 117.3 pounds of butter were made from each 100 
pounds of butter fat in the whole milk.^ The exact con- 
version factor would be 1.173. As this is an awkward 
number to use, and as If is so nearly the same ... it 
has seemed best to recommend that the latter be used as 
the conversion factor." 

A resolution was adopted by this association recom- 
mending that the approximate equivalent of butter be 
computed by multiplying the amount of butter fat by 1^. 

These figures are the result of more than ordinary care 
in skimming, churning and testing, and probably repre- 
sent the minimum losses of fat in the manufacturing pro- 
cesses. The increase of churn over test represented by 
one-sixth, or 16 per cent., may therefore be taken as a 
maximum ' 'overrun" under ordinary factory conditions. 
Butter makers who report overruns of 16-20 per cent, do 
not show their expertness in butter making by such high 
figures, but their lack of accuracy in testing, or careless- 
ness in working the butter; a large overrun may be ob- 
tained both by reading the test too low, and by leaving 
an excess of water in the butter, through insufScient 
working or other causes. 

219. Butter yield from milk of different richness, a. Use 
of butter chart. The approximate yield of butter from 
milk of different richness is shown in table XI in the 



1 When 82.37 ft>s. of butter fat will make 100 lbs. of butter, how much 
butter will 96.67 fts. of butter fat make? 82.37 : 96.67 : : 100 : x, x = 117.3. 



Calculation of Butter-- and Cheese Yield. 185 

Appendix. This table is founded on ordinary creamery 
experience and will be found to come near to actual 
every- day conditions of creameries where modern meth- 
ods are followed in the handling of the milk and its pro- 
ducts. The table has been prepared in the following 
manner: 

It is assumed that the average loss of fat in the skim milk is 
.20 per cent., and that 85 lbs. of skim milk is obtained from 
each 100 lbs. of whole milk; to this loss of fat is added that from 
the butter milk; about 10 lbs. of butter milk is obtained per 100 
lbs. of whole milk, testing on the average .30 per cent. 

If/ designate the fat in 100 fts. of milk, then the fat recov- 
ered in the butter from 100 lbs. of milk will be 

'f-(i|x.20+iix.30) = f-.20 

There is, on the other hand, an increase in weigth in the 
butter made, owing to the admixture of non-fatty components 
therein, principally water and salt. Butter packed and ready 
for the market will contain in the neighborhood of 84 per cent, 
of fat (213), so that the fat recovered in the butter must be in- 
creased by ^8*^4^ = 1. 19. If B therefore designate the yield of but- 
ter from 100 lbs. of milk, the following formula will express the 
relation between yield and fat content, provided there are no 
other factors entering into the problem, viz. : 
B=(f-.20) 1.19 

Certain mechanical losses are, however, unavoidable in the 
creamery, as in all other factory operations, viz., milk and 
cream remaining in vats and separators, butter sticking to the 
walls of the churn, etc. These losses have been found to aver- 
age about 3 per cent, of the total fat in the milk handled, under 
normal conditions and under good management (218); we 
therefore deduct this amount from the preceding value for B, 
and have: 

B=(f-.20) 1.16 

220. Table XI in the Appendix, founded on this form- 
ula, may be used to determine the number of pounds of 



186. Testing Milk and Its Products. 

butter which milk containing 3 to 5.3 per cent, fat will 
be likely to make. It presupposes good and careful 
work at the separator, churn and butter worker, and 
under such conditions will generally show yields of 
butter varying but little from those actually obtained. 
It may be conveniently used by the butter maker or the 
manager to check the work in the creamery; the average 
test of the milk received during a certain period is found 
by dividing the total butter fat received, by the total 
milk, and multiplying the quotient by 100; the amount 
of butter which the total milk of this average fat content 
will make, according to the table, is then compared with 
the actual churn yield. 

Example: A creamery receives 200,000 R)s. of milk during 
a month; the milk of each patron is tested and the fat con- 
tained therein calculated. The sum of these amounts of fat 
may be 7583 K)s.; the average test of the milk is then 3.79 
per cent. According to table X I, 10,000 tbs. of milk, testing 3.8, 
will make 418 K>s. of butter, and 200,000 R)s., therefore, 8360 ft»s. 
of butter. The total quantity of butter made during the month 
will not vary appreciably from this figure if the work in the 
creamery has been properly done. 

221. b. Use of overrun table. The table referred to 
above gives a definite calculated butter yield for each 
grade of milk, according to average creamery conditions. 
As it may be found that this table will give uniformly 
either too low or too high results, table XII in the Appendix 
is included, by means of which the butter yield cor- 
responding to overruns from 10-20 per cent, may be 
ascertained in a similar way as above described. 

The total yield of butter is divided by the total num- 
ber of pounds of fat delivered ; the quotient will give the 



Calculation of Butter- and Cheese Yield. 187 

amount of butter made from one pound of fat, and this 
figure multiplied by the fat delivered by each patron 
shows the pounds of butter to be credited to each patron. 
To use the table, find in the upper horizontal line the 
number corresponding most nearly to the number of 
pounds of butter from one pound of fat. The vertical 
column in which this falls gives the pounds of butter 
from 100 lbs. of milk containing the per cents, of fat 
given in the outside columns (Babcock^). 

B. — Calculation of Yield of Cheese. 

222. a. From fat. The approximate yield of green 
Cheddar cheese from 100 Hbs. of milk may be found by 
multiplying the per cent, of fat in the milk by 2.7; if/ 
designate the per cent, of fat in the milk, the formula 
will, therefore, be: 

Yield of cheese =2.7 f. (I) 

The factor 2. 7 will only hold good as the average of a 
large number of cases. In extensive investigations dur- 
ing three consecutive years, Yan Slyke ^ found that the 
number of pounds of green cheese obtained for each 
pound of fat in the milk varied from 2.51 to 3.06, the 
average figures for the three years 1892-'94, inch, 
being 2.73, 2.71, and 2.72 lbs. respectively. The richer 
kinds of milk will produce cheese richer in fat, and 
will yield a relatively larger quantity of cheese, pound 
for pound, than poor milk, for the reason that an in- 
crease in the fat content of milk is accompanied by an 

1 Woll, Handbook for Farmers and Dairymen, p. 307. 

2 N, y. experiment station (Geneva), bulletins No. 65 and 82. 



188 Testing Milk and Its Products. 

increase in the other cheese-producing solids of the milk.^ 
The preceding formula would not, therefore, be correct 
for small lots of either rich or poor milk, but only for 
milk of average composition, and for large quantities of 
normal factory milk. For cured cheese the factor will 
be somewhat lower, viz., about 2.6, on the average. 

223. b. From solids not fat and fat. If the percentages 
of solids not fat and of fat in the milk are known, the 
following formula by Babcock will give close results: 

Yield of green cheese =:1.58(^+. 91 f) . . (II) 
s being the per cent, of solids not fat in the milk, and/ 
the per cent, of fat. ^' 

The solids not fat can be readily ascertained from the 
lactometer reading and the per cent, of fat, as shown on 
p. 100, by means of table YI in the Appendix. 

Table XIII in the Appendix gives the yield of cheese 
from 100 Hbs. of milk containing from 2. 5 to 6. per cent, 
fat, the lactometer readings of which range between 26 
and 36. By means of this table cheese makers can cal- 
culate very closely the yields of cheese which certain 
quantities of milk will make; as it takes into considera- 
tion the non- fatty solids as well as the fat of the milk, 
the results obtained by the use of this formula will be 
more correct than those found by means of formula (I). 
The uncertain element in the formula lies in the factor 



1 Investigation as to the relation between the quality of the milk and 
the yield of cheese have been conducted by a number of experiment sta- 
tions; the following references give the main contributions published on 
this point; N. Y. (Geneva) exp. station, reports 10-13, incl.; Wis. exp. sta., 
reports 11 and 12; Ont. Agr. College, reports 1894-'96, incl; Minn. exp. sta., 
b. 19, reports 1892-'94, incl.; Iowa exp. sta., bull. 21; Hoards Dairyman, 1892, 
p. 2400. 

2 For derivation of this formula, see Wisconsin experiment station, 
twelfth report, p. 105. 



Calculation of Butter- and Cheese Yield. 189 

1.58, which, as shown above, is based on an average water 
content of 37 per cent, in the green cheese. This may, 
however, be changed to suit any particular case, e. g., 35 
percent (\^^-=1.54t), 40 per cent. (Jg\Q-==l-67), etc. The 
average percentages of water in green cheese found by 
Yan Slyke in his investigations referred to above, were 
for the years 1892-'94, respectively, 36.41, 37.05 and 
36. 70 per cent. 

224. c. From casein and fat. If the percentages of 
casein and fat in the milk are known, the yield of cheese 
may be calculated by the following formula, also pre- 
pared by Dr. Babcock: 

Yield of cheese=l.l f+2.5 casein , . . (III). 

This formula will give fairly correct results, but no 
more so than formula (II); it is wholly empirical. 



CHAPTEE XIII. 
CALCULATING DIVIDENDS. 

A. — Calculating Dividends at Creameries. 

225. The simplest method of calculating dividends at 
creameries is to find the number of pounds of butter fat 
delivered to the creamery by each patron for a certain 
length of timCj and then multiply this number by the 
price per pound of fat. Farmers are usually paid once 
a month for their milk at the factory. Each lot of milk 
is weighed when delivered at the creamery, and a small 
quantity thereof is saved for the composite sample, as 
previously explained under Composite tests (176). 
Some creameries test these samples at the end of each 
week, and others after collecting them for ten days or 
two weeks. If the foar weekly composite samples of a 
patron's milk tested 3.8, 4.0, 3.9, 4.1 per cent., these 
four tests are added together, and the sum divided by 4; 
the result, 3.95 per cent., is used as the average test of 
this milk. By multiplying the total number of pounds 
of milk delivered by this patron, by his average test, the 
total weight in pounds of butter fat delivered to the fac- 
tory during the month is obtained. This weight of fat is 
then multiplied by the price to be paid by the creamery 
per pound of butter fat; the product shows the amount 
of money due this patron for the milk delivered during 
the time samples were taken. 

226. Price per pound of butter fat. The method of ob- 
taining the price to be paid for one pound of butter fat 



Calculating Dividends. 191 

varies some what in different creameries, on account of 
the different ways of paying for the cost of manufacturing 
the butter. The method to be followed is generally deter- 
mined by agreement between the manufacturer and the 
milk producers, in case of proprietary creameries, or be- 
tween the shareholders, in co operative creameries. The 
following methods of paying for the cost of manufacture 
are at the present time met with in American creameries. 

227. I. Proprietary creameries. i^ir«t— When the 
creamery is owned by some one person or cf>mpany, the 
owner or owners agree to make the butter for about 3 cents 
a pound 5 the difference between the total receipts of the 
factory and the amount due the owner is then divided 
between the different patrons, according to the amount of 
butter fat contained in the milk which they delivered. 

In the majority of cases, the price charged for making 
butter is now 3 cents a pound; 2f and 2 J cents are some- 
times charged. The larger the amount of milk received 
at a factory, the lower will naturally be the cost of man- 
ufacturing the butter.^ 

Second. — The proprietor of the creamery sometimes 
agrees to pay a certain price for 100 lbs. of milk deliv- 
ered, according to its fat content, the price of milk con- 
taining 4 per cent, of butter fat being the standard. This 
price may change daring the different seasons of the year 
by mutual agreement. 

Third. — A creamery owner may offer to pay 1 to 2 
cents, usually 1^ cents below the average market price of 
butter, for each pound of butter fat received in the milk. 

228. II. Co-operative creameries. In this case, where 
the creamery is owned by the patrons, one of the stock - 

1 Wisconsin experiment station, bull. 56, p. 26. 



192 Testing Milk and Its Products. 

holders who is elected secretary attends to the details of 
running the factory and selling the product. His ac- 
counts show the amount of money received each month 
for the butter and other products sold, and the expenses 
of running the factory during this time. The expenses 
are subtracted from the receipts, and the balance is 
divided among the patrons, each one receiving his pro- 
portionate share according to the amounts of butter fat 
delivered in each case (as shown by the total weight and 
the average test of milk delivered during this time). 

In nearly all cases, the farmers receive about eighty 
pounds of skim milk for each hundred pounds of whole 
milk they deliver to the factory, in addition to the 
amount received for the milk, calculated according to 
one or the other of the preceding methods. 

229. Illustrations of calculations of dividends. In order 
to illustrate the details of calculating dividends, or the 
amount to be paid each patron for the milk supplied 
each month, when payments are made by each of the 
four systems given, it will be assumed that a creamery 
receives 5000 pounds of milk daily for thirty days, and 
makes 6650 lbs. of butter from the 150,000 Hbs. of milk 
received during this time. The average test of this milk 
may be found by multiplying the total weight of milk 
delivered by each patron by his average test, and divid- 
ing the sum of these products by the total weight of milk 
received at the creamery (in the example given, by 150,- 
000), the quotient being multiplied by 100. Such calcu- 
lations may show that, e. g., 5700 lbs. of butter fat have 
been received in all in the milk delivered by the differ- 
ent patrons; this multiplied by 100 and divided by 



Calculating Dividends. 



193 



150,000 gives 3.8 as the average test, or the average 
amount of butter fat in each 100 tbs. of milk received 
during the month. 

So far the method of calculation is common for all dif- 
ferent systems of payment given above; the manner of 
procedure now differs according to the agreement made 
between owner and patrons, or between the shareholders, 
iu case of co-operative creameries. 

230. I. First— U the net returns for the 6650 lbs. of 
butter sold during the month were $1197, and the cream- 
ery is to receive 4 cents per pound of butter as the cost of 
manufacture, etc., the amount due the creamery is 
6650 X. 04 =$266, and the patrons would receive $1197— 
$266 =$931. This sum, $931, is to be paid to the patrons 
for the 5700 lbs. of butter fat, which, as shown above, 
was the weight of fat contained in the 150,000 Hbs. of 
milk delivered during the month. The price of one 
pound of butter fat is then easily found: $931-^5700 = 
16J cents. This price is paid to all patrons for each 
pound of butter fat delivered in their milk during the 
month. The monthly milk record of three patrons may, 
e. g., be given in the following table: 





First 


week 


Second week 


Thirdweek 


Fourth week 


Total 

Milk 

lbs. 


Patrons 


Milk 

K)S. 


Test 
pr.ct. 


Milk 

ibs. 


Test 
perct. 


Milk 

fts. 


Test 
prct. 


Milk 

fts. 


Test 
perct. 

3.45 

3.7 

3.6 


No. 1 

" 2 

" 3 


3500 
700 

2480 


3.6 
3.8 
4.2 


3000 

665 

2000 


3.5 
3.8 
3.8 


3600 
720 

1850 


3.65 

3.6 

4.0 


3450 

750 

1500 


13,550 

2,825 
7,830 



3.55 
3.73 
3.93 



Multiplying each patron's total milk by his average 
test gives the number of pounds of butter fat in his milk, 

13 



194 



Testing Milk and Its Products. 



and this figure multiplied by . 16 J shows the money due 
for his milk, as given below: 



Patron. 


Total milk 

tt)S. 


Average test 
per cent. 


Batter fat, 
lbs. 


Price Qf fat 
per a., cents. 


Amounts 
due. 


No. 1 


13,550 

2,825 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 
305.4 




$78. 56 


No 2 


17.06 


No. 3 


48.96 







23L Second. — When the proprietor of a creamery 
agrees to pay a certain price for 100 libs, of 4 per cent, 
milk, the receipts for butter sold and the price per pound 
of butter do not enter into the calculation of the amount 
due each patron for his milk; but the weight and the 
test of each patron's milk are just as important as before. 
If it is agreed to pay QQ cents per 100 lbs. of 4 per cent. - 
milk (i. e., milk containing 4 per cent, of butter fat), 
the price of one pound of butter fat will be 66-^4 = 161^ 
cents, and the amount due each patron is found by multi- 
plying the total weight of butter fat in his milk by this 
price. To facilitate this calculation, so-called Relative- 
Value Tables have been constructed, the use of which is 
explained below (237). 

232. Third. — If a creamery agrees to pay for butter fat, 
say 1^ cents per pound below the average market price 
of butter each month, the price of one pound of butter 
fat is found by averaging the market quotations and sub- 
tractiog IJ cents therefrom. If the four weekly market 
prices were 17 J, 17, 16 J and 19 cents, the average of these 
would be n^ cents, and this less 1-|- gives 16 cents as the 
price per pound of fat to be paid to the patrons; this 
price is then used in calculating the dividends as in case 
of first method (230). 



Calculating Dividends. 



195 



Patron. 


Total milk 

lbs. 


Average test 
per cent. 


Butter fat, 
fts. 


Price of fat, 
per lb., cents. 


Amounts 
due. 


No. 1 


13,550 

2,825 
7,830 


3.55 

3.7 

3.9 


^81.0 
104.5 
305.4 


16 
16 
16 


$76 96 


No 2 .. 


16 72 


No. 3 


48.86 



233. II. If the creamery is owned by the farmers, the 
running expenses for a month are subtracted from the 
gross returns received for the butter, and the price to be 
paid per pound of butter fat is found by dividing the 
amount left, by the total number of pounds of butter fat 
delivered during the month. This price is used for pay- 
ing each patron for his milk according to the amount of 
fat contained therein, as already explained under Pro- 
prietary Creameries (230). 

The monthly running expenses of a co-operative cream- 
ery generally include such items as the wages of the 
butter maker (and manager or secretary, if these officers 
are salaried), labor (hauling, helper, etc.), cost of butter 
packages, coal or wood, salt and other supplies, freight 
and commission on the butter sold, repairs and insurance 
on buildings, etc. A certain amount is also paid into a 
sinking fund (say 5 cents per 100 lbs. of milk), which 
represents the depreciation of the property, wear and 
tear of building and machinery, bad debts, etc. These 
items are added together, and their sum subtracted from 
the gross receipts for the butter sold during the month. 

234. Assuming the receipts for the butter during the 
month to be $1197, and the running expenses of the fac- 
tory $285, the amount to be divided among the patrons 
is $912 5 the quantity of butter fat received was 5700 lbs., 



196 Testmg Milk and Its Products. 

and the price per pound of butter fat will therefore be 16 
cents. The account will then stand as given in (232). 

235. Other systems of payment. Besides these four 
systems of payment, there are various other agreements 
made between manufacturer and producer, but with 
them all the one important computation is the price to 
be paid per pound of butter fat: this forms the basis of 
calculating the factory dividends, when milk is paid for 
by the Babcock test. 

236. Paying for butter delivered. In some instances 
patrons desire to receive pay for the quantity of butter 
which the milk delivered by them will make. This can 
be ascertained quite accurately from the total receipts 
and the total weights of both butter fat and butter. The 
total money to be paid for butter (the net receipts) are 
divided by the number of pounds of butter sold, to get 
the price to be paid per pound of butter; the total yield 
of butter divided by the total amount of butter fat de- 
livered in the milk, gives the amount of butter corre- 
sponding to one pound of butter fat, and the pounds of 
fat delivered by each patron is then multiplied by this 
figure. This method requires more figuring than those 
given in the preceding, and the dividends are no more 
accurate, in fact less so, than when calculations are based 
on the price per pound of fat. 

237. Relative value tables. These tables give many of 
the multiplications used in computing the amount due 
for various weights of milk testing from 3 to 6 per cent, 
of fat. They can be easily constructed by any one as 
soon as the price of one pound of fat is determined in 
each case. If the price to be paid per pound of fat is 



Calculating Dividends. 197 

say 15 cents, the value of each 100 lbs. of milk of differ- 
ent quality is found by multiplying its test by 15. If the 
average tests of the different patrons' milk vary from 3 
to 5 per cent., the relative- value table would be as 
follows: 



3.0xl5=45c. per 


100 lbs. 


3.6Xl5=r54c. per 


100 Itjs. 


3.1Xl5=46.5c. 


u 


3.7Xl5=55.5c. 


a 


3.2xl5=48c 




3.8Xl5=57c. 


u 


3.3Xl5=49.5c. 


li 


3.9xl5=r58.5c. 


(< 


3.4xl5=51c. , 


(( 


4. Ox 15= 60c. 


u 


3.5Xl5=52.5c. 


(t 


etc. 





By continuing this multiplication, or adding the mul- 
tiplier each time for each tenth of a per cent, up to 5 per 
cent, of fat, a table is made that can be used for calcu- 
lating the amount due per 100 lbs. of milk, at this price 
per pound, and the weight of milk delivered by each 
patron is multiplied by the price per 100 lbs. of milk 
shown in the table opposite the figure representing his 
test. 

Example: A patron supplies 2470 lbs. of milk, testing 3.2 
per cent, of fat; price per pound of fat, 15 cents; he should then 
receive 24.70x.48=$11.85 (see above table). Another patron 
delivering 3850 R)s. of milk testing 3.8 per cent, will receive, at 
the same price per pound of fat, 38.50 x.57=$21. 94. 

The relative value tables in the Appendix give the 
price per 100 lbs. of milk testing between 3 and 6 per 
cent, fat, when the price of three per cent, milk varies 
from 30 to 90c. per 100 lbs. In using the tables, first 
find the figure showing the price which it has been de- 
termined to pay for 100 lbs. of milk of a certain quality, 
say 3 or 4 per cent. -milk; the figures in the same vertical 
column then give the price to be paid per 100 lbs. of 
milk testing between 3 and 6 per cent. 



198 



Tenting Milk and Its Products. 



Example 1: It has been decided to pay 90 cents per 100 R)s. 
of 4 per cent. -milk. The figure 90 is then sought in the table in 
the same line as 4.0 percent., and the vertical column in which 
it is found gives the price per 100 lbs. of 3 to 6 per cent. -milk, 
3.8 per cent. -milk is thus worth 85 cents per 100 lbs. and 4.5 per 
cent-milk, |1.01, under the conditions given. The prices of 
milk of other qualities are found in the same way. 

Example 2: In the example referred to under Illustrations 
of calculating creamery dividends (I b, 231), the figures for the 
patrons Nos. 1, 2 and 3, would be as follows: 



Patron. 


Milk delivered, 
lbs. 


Average 

test. 


Price per 100 fts. 
of milk, cents. 


Amounts 
due. 


jSTo. 1 


13,550 

2,825 
7,830 


3.55 

3.7 

3.9 


58.5 
61.0 
64.0 


$79.26 


" 2 


17.23 


'« 3 


50.11 







238. Milk- and cream dividends. When cream from 
farm hand separators or other sources is brought to a 
factory receiving and skimming whole milk, the cream 
patron's dividend should be calculated a little differently 
than that of the Inilk patron. 

In one case the dividend is based on the weight and the 
test of cream and in the other on the weight and the test 
of milk; the difference between the two being represented 
by the fat left in the factory skim milk. This skim milk 
fat is included in the milk patron's dividend and conse- 
quently ought also to be allowed for in calculating the 
amount due the cream patron. Such an allowance can 
be fairly made by multiplying the cream fat by 1.03. 
This is assuming that the one- tenth or more of fat re- 
turned to the milk patron in his skim milk is about 
three per cent, of the total fat in his whole milk. 

Both milk and cream patron suffer the same manufac- 
turing loss in the factory butter milk so that an equaliza- 



Calculating Dividends. 199 

tion of the skimming losses is all that is necessary in order 
to put both on a uniform basis for calculating dividends. 

239. The following illustration may help to make these 
calculations clearer. Milk patron No. 1 may deliver to 
the creamery during the month 5320 lbs. of milk testing 
3.8 per cent. fat, which therefore contains ( ^^^oxs.s )^202 
lbs. butter fat. If the price paid the patrons is 20c 
then the 202 lbs. x20c amounts to $40.40, the money due 
this patron for his milk. If, however, another patron 
sent 485 lbs. of cream testing 22.0 per cent, fat to the 
same factory during the month, the weight of fat in the 
cream is first found in the same way as in the milk. 
(^-^^2) =106. 7 lbs. butter fat. Now instead of multi- 
tiplying this butter fat by 20c as was done for the milk 
patron it must first be multiplied by 1.03 which makes 
the necessary alio trance for the skim milk fat that the 
milk patron was paid for. 106.7 X 1.03 = 109. 9' lbs. but- 
ter fat which is now multiplied by 20c per pound, giving 
$21.98. This is the amount due the cream patron when 
both milk and cream are received at the same factory 
and the cream from both patrons is churned together. ^ 

B. — Calculating Dividends at Cheese Factories. 

240. The amount of cheese made from a certain quan- 
tity of milk depends, as before shown, in a large measure 
on the richness of the milk in butter fat (222). Rich milk 
will give more cheese per hundred weight than poor milk, 
and within the ordinary limits of normal factory milk the 
increased yields will be nearly, but not entirely, pro- 
portional to the fat contents of the different kinds of 

1 17th Report Wis. expt. station, p. 90; 20th report, pp. 130-131. 



200 Testing Milk and Its Products. 

milk. Since the quality of the cheese produced from 
rich milk is better than that of cheese made from thin 
milk and will demand a higher price, it follows that no 
injustice is done by rating the value of milk for cheese 
production by its fat content. This subject has been 
discussed frequently during late years in experiment 
station publications and in the dairy press (222). Among 
others, Babcock has shown that the price of cheese 
stands in a direct relation to its fat content.^ Prof. Eob- 
ertson, Commissioner of Agriculture of Canada, is author- 
ity for the statement that the quality of the cheese made 
from milk containing 3.0 to 4.0 per cent, of fat was in- 
creased in value by one- eight of a cent per pound for 
every two- tenths of a per cent, of fat in the milk/ a 
figure which is fully corroborated by Dr. Babcock' s 
results. The injustice of the "pooling system", by 
which all kinds of milk receive the same price, is evi- 
dent from the preceding; if the milk of a certain patron 
is richer than that of others, it will make a higher grade 
of cheese, and more of it per hundredweight; hence a 
higher price should be paid for it. 

Payment on the basis of the fat content of milk is, 
therefore, the most equitable method of valuing milk for 
cheese making, and in case of patrons of cheese factories 
as with creamery patrons, dividends should be calcu- 
lated on the basis of the results obtained by testing the 
milk delivered. The testing may be conveniently ar- 
ranged by the method of composite sampling, in the way 
already described for creameries (176). 



1 Wisconsin exp. station, 11th report, p. 134. 

2 Hoard's Dair^'man, March 29, 1895. 



Calculating Dividends. 201 

241. Calculation of dividends. As with creameries, the 
first thing to be ascertained is the price to be paid per 
pound of butter fat. The factory records should show 
the number of pounds of cheese made from the total milk 
delivered to the factory during a certain time, generally 
one month, and the money received for this cheese. The 
cost of making the cheese and all other expenses that 
should be paid for out of the money received for the 
cheese, are deducted from the total receipts, and the dif- 
ference is divided among the patrons in proportion to 
the amounts of butter fat delivered in the milk. 

The weights of the milk delivered and the tests of the 
composite samples furnish data for calculating the quan- 
tities of butter fat to be credited to each patron. The 
money to be paid to the patrons is then divided by the 
total weight of butter fat delivered to the factory and the 
price of one pound of fat thus obtained. The money due 
each patron is now found by multiplying the total num- 
ber of pounds of butter fat in his milk by this price per 
pound. 

The illustrations already given for calculating patrons' 
dividends at creameries according to the various methods 
will serve equally well to show the manner in which 
dividends are calculated at a cheese factory. For the 
sake of clearness an example is given that applies directly 
to cheese factories. 

242. illustration of calculation of dividends. It may 
be assumed that 15,000 lbs. of green cheese is made 
from 150,000 lbs. of milk delivered to a factory in a 
month. According to the weighings and the tests made, 
the milk contained 5, 700 lbs. of butter fat. If the cheese 



202 



Testing Milk and Its Products. 



sold at an average price of 7 J cents a pound, the gross 
receipts would be $1, 125. 00. The amount to be deducted 
from the gross receipts will depend on the agreement 
made between the factory operator and the patrons, in 
case of proprietary cheese factories, or between the 
shareholders and the maker, when the factory is run on 
the co-operative plan. As before we shall consider these 
systems separately. 

243. I. Proprietary cheese factories. The owner of the 
factory generally agrees to make the cheese for a certain 
price per pound and to pay the patrons what is left after 
deducting this amount. If the price agreed on is 1\ 
cents per pound of green cheese, this would amount to 
$225 in the example given. Subtracting this sum from 
the gross receipts, $1,125, leaves $900, which is to be 
paid the patrons. The total amount of butter fat deliv- 
ered by the patrons was 5, 700 fbs. ; hence the price of one 
pound of butter fat will be 900^5,700^.1577, or 15.8 
cents. Taking the figures for the three patrons already 
mentioned under Creamery Dividends, we then have: 



Patron. 


Total milk, 

K)S. 


Average 

test, 
per cent. 


Butter fat, 

lbs. 


Price per lb. 
of fat, 
cents. 


Amounts 
due. 


No. 1 


13,550 

2,825 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 

305.4 


15.8 
• 15. 8 
15.8 


$76.00 


No. 2 


16.51 


No. 3 


48.25 







244. II. Co-operative cheese factories. The method 
of payment at co-operative cheese factories is nearly the 
same as that already given, except that a certain sum 
representing the expenses is subtracted from the gross 
receipts for the cheese, and the balance is divided among 



Calculating Dividends. 203 

the patrons according to the amount of butter fat fur- 
nished by each, in the same manner as in the above case, 
after the price of a pound of fat has been obtained. 

The price per 100 lbs. of milk can be calculated in the 
same way as at creameries, by multiplying the test of 
each lot by the price per pound of fat. ^ 

1 Suggestions regarding the organization of co-operative creameries 
and cheese factories will be found in the Appendix, following Table XV. 
Draft of constitution and by-laws for co-operative factory associations are 
also given in the Appendix. It is hoped that these will prove helpful to 
farmers who contemplate forming such associations. 



CHAPTEE XIV. 
CHEMICAL ANALYSIS OP MILK AND ITS PRODUCTS. 

245. An outline of the methods followed in determin- 
ing quantitatively the main components of milk and its 
products is given in the following for the guidance of 
more advanced dairy students. This work cannot be 
done outside of a fairly well- equipped chemical labora- 
tory, or by persons who have not been accustomed to 
handling delicate chemical apparatus and glassware, 
analytical balances, etc., and who have not a knowledge 
of, at least, the elements of chemistry and chemical 
reactions. 

A. —Milk. 

246. In a complete milk analysis, the specific gravity 
of the milk is determined, and the following milk com- 
ponents: water, fat, casein and albumen, milk sugar, 
and ash. The methods of analysis described in the fol- 
lowing are those used in the chemical laboratory of the 
Wisconsin experiment station, which in the main are the 
same as those adopted by the Association of Official 
Agricultural Chemists, and with but slight modifications, 
in general use in the chemical laboratories of all Ameri- 
can experiment stations and agricultural colleges.^ 

247. a. Specific gravity is determined by means of a 
picnometer or specific- gravity bottle, since more accurate 

1 The methods of analysis adopted by the Association of OfScial Agri- 
cultural Chemists are published by the Chemical Division of the U. S. 
Department of Aerno.nitnre; see Bull. No. 4fi, revised edition, p. 54. 



Chemical Analynn of Milk and Its Products. 205 

results will thus be reached than by using an ordinary 
Quevenne lactometer. A thermometer is ground into 
the neck of the specific-gravity bottle so as to form a 
stopper, and the bottle is provided with a glass stoppered 
side-tube, to furnish an exit for the liquid on expanding. 
A specific-gravity bottle holding 100 grams of water is 
preferably used. The empty and scrupulously cleaned 
bottle is first weighed on a chemical balance. The bot- 
tle is then filled with recently-boiled distilled water of a 
temperature below 60° F. (15.5° C. ); the thermometer 
is inserted, and the bottle is warmed slightly by immers- 
ing it for a moment in tepid water and left standing until 
the thermometer shows 60° F. ; the opening of the side 
tube is then wiped off and closed with the stopper, and 
the water on the outside of the bottle and in the groove 
between its neck and the thermometer is wiped off with 
filter paper or a clean handkerchief, when the bottle is 
again weighed. , The weight being recorded, the bottle is 
emptied and dried in a water oven, or if sufficient milk 
is at hand, the bottle is repeatedly rinsed with the milk, 
the specific gravity of which is to be determined. It is 
then filled with milk in a similar manner as in case of 
water; the temperature of the milk should be slightly 
below 60° F. and is slowly brought up to this degree 
after the bottle has been filled, proceeding in the same 
way as before with water; the weight of the bottle and 
milk is then taken. 

The weights of water and of milk contained in the 
specific-gravity bottle are found by subtracting the 
weight of the empty bottle from the second and the third 
weights, respectively, and the specific gravity of the milk 



206 Testing Milk and Its Products. 

then found by dividing the weight of the milk by that of 
the water. 

Example: Weight of sp. gr. bottle+water...l46.9113 grams. 
Weight of sp. gr. bottle empty 46.9423 " 

Weight of water 99.9690 grams. 

Weight of sp. gr. bottle+milk 149.8708 grams. 

Weight of sp. gr. bottle empty.... 46.9423 " 

Weightof milk ...102.9285 grams. 

Sp.gr. of milk='-|;|f =1.0296 

248. If a plain picnometer without a thermometer attached, 
is available, the method of procedure is similar to that described, 
with the difference that the temperature of the water and of 
the milk must be brought to 60° F. before the picnometer is 
filled, or the picnometer filled with either liquid is placed in 
water in a small beaker, which is very slowly warmed to 60° F. 
and kept at this temperature for some time so as to allow the 
liquid in the picnometer to reach the temperature desired; the 
temperature of the water in the beaker is ascertained by means 
of an accurate chemical thermometer. The perforated stopper 
is then wiped off, the picnometer is taken out of the water, 
wiped and weighed. It is necessary to weigh very quickly if 
the room temperature is much above 60° F., as in such cases the 
expanding liquid will flow on to the balance pan, with a re- 
sultant loss in weight from evaporation. 

The weights of specific-gravity bottle or picnometer, empty 
and filled with water, need only be determined a couple of 
times, and the averages of these weighings are used in subse- 
quent determinations. 

249. Westphal balance. Where only a small amount 
of milk is available, or in rapid work, the specific grav- 
ity may be taken with . considerable accuracy by means 
of a Westphal balance. The arrangement and use of 



Chemical Analysis of Milk and Its Products. 207 

this conveDieat little apparatus is readily explained 
verbally. 

For the determination of the specific gravity of loppered 
milkj see 260. 

250. b. Water. The milk is weighed into a perforated 
copper tube filled with prepared dry asbestos. The tubes 
are made from perforated sheet copper, with holes about 
.7 mm. in diameter and about .7 mm. apart; they are 
60 mm. long, 20 mm. in diameter and closed at the bot- 
tom. The asbestos is prepared from clean fibrous asbes- 
tos, which is ignited at low heat in a muffle oven, treated 
with a little dilute HCl (1:3) and then with distilled 
water till all acid is washed out; it is then torn in loose 
layers and dried at a low temperature in an air bath; 
when dry it can be easily shredded in fine strings and is 
placed in a wide- mouth, glass- stoppered bottle. 

About two grams of asbestos are placed in each tube, 
packing it rather loosely; the tube is then weighed, a 
small narrow beaker being inverted over it on the scale 
pan. 5 cc. of milk are now dropped on to the asbestos 
from a 5 cc. fixed pipette, the beaker again placed over 
the tube, and the weight of the 5 cc. of milk delivered 
+copper tube taken. The weight of the milk is ob- 
tained by difference. The tubes are then placed in a 
steam oven and heated at 100° C. until they no longer 
decrease in weight, which ordinarily will take about 
three hours. Place in desiccator until cold, and weigh ; 
the difference between the weight of the tube+milk and 
this last weight gives the water contained in the milk, 
which is then calculated in per cent, of the quantity of 
milk weighed out. 



208 Testing Milk and Its Products. 

Example: Weight of tube+beaker+milk 29.3004 grams. 

Weight of tube+beaker 24.1772 " 

Milk weighed out 5.1232 grams. 

Weight of tube+beaker-f-milk 29.3004 grams. 

Weight of tube-f beaker+milk, dry 24.9257 ' ' 



Weight of water 4.3747 grams. 

Per cent, of water in milk=^-^-j^^ — =85.39 per cent. 

Note. The per cent, of total solids in milk is often given, 
instead of that of water; this may be readily obtained by 
subtracting the weight of the empty tube from that of 
the tube filled with milk solids, and finding the per cent, 
of the milk weighed out which this difference makes. In 
the above example, the weight of milk solids thus is 
24.9257-24.1772=1.7485 grams, and the per cent, of 
total solids in the milk = 14. 61 per cent. 

251. Alternate method. Five cc. of milk are measured out on 
a weighed flat porcelain dish (50-60 mm. in diameter; porcelain 
crucible covers will answer the purpose better than any other 
vessel on the market, provided the handle be broken off or 
ground off level on an emery wheel); this is weighed rapidly; 
two or three drops of 30 per cent.-acetic acid are added, and the 
dish is dried in a steam oven at 100° C. until no further loss in 
weight is obtained. After cooling in desiccator, the weight of 
the milk solids is obtained, and by calculation as before, the 
per cent, of water or total solids in the milk. 

252. c. Fat. The dried tubes from the water determi- 
nation are placed in Caldwell extractors and connected 
with weighed, numbered glass flasks (capacity, 2-3 oz.); 
the extractors are attached to upright Liebig condensers 
and the tubes extracted with pure ether, free from water, 
alcohol or acid, until all fat is dissolved; 4-5 hours' ex- 
traction is sufficient for whole milk; in case of samples of 



Chemical Analysis of Milk and Its Froduds. 209 

skim milk it is well to continue the extraction for 8 hours. 
The ether is then distilled off and recovered, and the 
flasks dried in a copper oven until constant weight ; after 
cooling they are weighed, and the amount of fat contained 
in the quantity of milk originally weighed into the tubes 
is thus ascertained, and the per cent, present in the milk 
calculated. 

Example: Weight of flask + fat. 15.8039 grams. 

Weightofflask 15.5171 " 

Weight of fat 2868 grams. 

Milk weighed out 5.1232 grams. 

Per cent, of fat in milk=^^f^|g^=5.60 per cent. 

253. d. Casein and albumen. The sum of these compo- 
nents is generally determined by the Kjeldahl method.^ 
5 cc. of milk are measured carefully into a flat- bottom 
800 cc. Jena flask, 20 cc. of concentr.tted sulfuric acid 
(C. P.J sp. gr., 1.84) are added, and .7 gram of mercuric 
oxid (or its equivalent in metallic mercury); the mixture 
is then heated over direct flame until it is straw-colored 
or perfectly white; a few crystals of potassium perman- 
ganate are now added till the color of the liquid remains 
green. All the nitrogen in the milk has then been con- 
verted into the form of ammonium sulfate. After cooling, 
200 cc. of ammonia- free distilled water are added, 20 cc. 
of a solution of potassium sulfid (containing 40 grams 
sulfld per liter), and a fraction of a gram of powdered 
zinc. A quantity of semi normal HCl-solution, more 
than sufficient to neutralize the ammonia obtained in the 
oxidation of the milk, is now carefully measured out 
from a delicate burette (divided into^ioCc. ) into an 



1 Fresenius' Zeitschrift, 22, p. 366; U. S. Dept. Agr., Ohem. Div., bull. 46. 
14 



210 ' Testing Milk arid Its Products. 

Erlenmeyer flask, and the flask connected with a distilla- 
tion apparatus. At the other end, the Jena flask con- 
taining the watery solution of the ammonium sulfate is 
connected, after adding 50 cc. of a concentrated soda 
solution (1 pound ^ 'pure potash" dissolved in 500 cc. of 
distilled water and allowed to settle) ; the contents of the 
Jena flasks are now heated to boiling, and the distillation 
is continued for forty minutes to an hour, until all 
ammonia has been distilled over. 

The excess of acid in the Erlenmeyer receiving- flask 
is then accurately titrated back by means of a tenth- 
normal standard ammonia-solution, using a cochineal- 
solution^ as an indicator. From the amount of acid 
used, the per cent, of nitrogen is obtained; and from it, 
the per cent, of casein and albumen in the milk by multi- 
plying by 6.25.^ The amount of nitrogen contained in 
the chemicals used is determined by blank experiments 
and deducted from the nitrogen obtained as described. 

Example: The weight of 5 cc. of milk (as obtained in deter- 
mining the water in the milk) was 5.1465 grams. 5 cc. of stand- 

N 

ard HCl are added to the receiver, and 1.55 cc. of ^ alkali- 
solution are used in titrating back the excess of acid. 1.55 cc. 
of ^ alkali — ^^=.51 cc. -tt acid-solution; the ammonia dis- 

10 5 .^ 

tilled over therefore neutralized 5.00— .51=4.49 cc. acid. By 
blank trials it was found that the reagents used furnished an 
equivalent of .02 cc. acid in the distillate; this quantity sub- 
tracted from the acid-equivalent of the nitrogen of the milk 
leaves 4.47 cc. 1 cc. semi-normal HCl-solution corresponds to 

N 

7 milligrams or .007 grams of nitrogen; 4.47 cc. -^ HCl therefore 



1 Sutton, Volumetric Analysis, 4th edition, p. 31. 

2 The factor 6.30 or 6.37 is more correct for the albumincjids of milk, but 
has not yet been generally adopted (p. 15, foot note). 



Chemical Analysis of Milk and Its Products. 211 

represents .03129 gram of nitrogen. This quantity of nitrogen 
was obtained from the 5.1465 grams of milk measyred out; the 

03129x1^0 

milk therefore contains ' ^^„ =.608 per cent of nitrogen, 
and .0608X6.25=3.80 per cent, of casein and albumen. 

254. Casein and albumen may be determined separately 
by Van Slyke's method;^ 10 grams of milk are weighed 
out and diluted with about 90 cc. of water at 40°-42° 0. 
1.5 cc. of a 10 per cent, acetic- acid solution are then 
added; the mixture is well stirred with a glass rod and 
the precipitate allowed to settle for 3-5 minutes. The 
whey is decanted through a filter and the precipitate 
washed two or three times with cold water. The nitro- 
gen is determined in the filter paper and its contents by 
the. Kjeldahl method; blank determinations with the 
regular quantities of chemicals and the filter paper used 
are made, and the nitrogen found therein deducted. 
The per cent, of nitrogen obtained multiplied by 6.25 
gives the per cent, of casein in the milk. 

255. Albumen is determined in the filtrate from the 
casein- precipitate; the filtrate is placed on a water bath 
and heated to boiling temperature of water for ten to 
fifteen minutes. The washed precipitate is then treated 
by the Kjeldahl method for the determination of nitro- 
gen; the amount of nitrogen multiplied by 6.25 gives the 
amount of albumen in the milk. The difference between 
the total nitrogenous components found by the Kjeldahl 
method, and the sum of the casein and the albumen, as 
given above, is due to the presence in milk of a third 
class of nitrogen compounds (18). 



1 Bulletin No. 46, p. 189, Chemical Division, U. S. Dept. of Agriculture. 



212 Testing Milk and Its Products. 

256. e. Milk sugar is generally determined by differ- 
ence, thesu'nioffat, casein and albumen (total Kx 6.25), 
and ash, being subtracted from the total solids. It may 
be determined directly by means of a polariscope, or 
gravimetrically by Fehling's solution; only the former 
method, as worked out by Wiley, ^ will be given here. 

The specific gravity of the milk is accurately deter- 
mined, and the following quantities of milk are measured 
out by means of a 100 cc. pipette graduated to .2 cc. (or 
a 64 cc. pipette made especially for this purpose, with 
marks on the stem between 63.7 and 64.3 cc. ), according 
to the specific gravities given: 1.026, 64.3 cc. ; 1.028, 
64.15 cc; 1.030, 64.0 cc; 1.032, 63.9 cc ; 1.034, 63.8 cc ; 
1.036, 63.7 cc These quantities refer to the Schmidt- 
Haensch half-shadow polariscopes, standardized for a 
normal weight of 26.048 grams of sugar. The milk is 
measured into a small flask graduated at 100 cc. and 
102.6 cc; 30 cc. of mercaric-iodid solution (prepared 
from 33.2 grams potassium iodid, 13.5 grams mercuric 
chlorid, 20 cc. glacial acetic acid and 640 cc. water) are 
added; the flask is filled to 102.6 cc. mark with distilled 
water, the contents mixed, filtered through a dry filter, 
and when the filtrate is perfectly clear, the solution is 
polarized in a 200 millimeter tube. The reading of the 
scale divided by 2, shows the per cent, of lactose (milk 
sugar) in the milk. Take five readings of two different 
portions of the filtrate, and average the results. 

257. f. Ash. About 20 cc of milk are measured into 
a flat-bottom porcelain dish and weighed; about one-half 
of a cc. of 30 per cent. -acetic acid is added, and the milk 

1 Agricultural Analysis, ill, p. 275; Am. Chem. Jour., 6, p. 289 et seq. 



Chemical Analysis of Milk and Its Products. 213 

first dried on water bath and then ignited in a muffle oven 
at a low red heat. Direct heat should not be applied in 
determining the ash of milk, since alkali chlorids are 
likely to be lost at the temperature to which milk solids 
have to be heated to ignite all organic carbon. 

Example: Weight of porcelain dish+milk 49.0907 grams. 

Weight of porcelaiu dish 28.3538 grams. 

Weight of milk 20.7369 grams. 

Weight of dish -|-miik, after ignition 28.5037 grams. 
Weight of dish 28.3538 grams. 

Weight of milk ash 1499 gram. 

-r, . f u .1499X100 ^,, . 

Per cent, of ash= 20 7869 ~-^^ P®^ cent. 
The residue from the determination of solids (251) 
may also be used for the ash determiuation. 

258. Acidity of milk. The acidity of milk is conven- 
iently determined by 'means o'f Farrington's alkaline 
tablets (see p. 120), or by one-tenth normal soda solu- 
tion. In the latter case 20 cc. of milk are measured into 
a porcelain casserole; a few drops of an alcoholic phe- 
nolphtalein solution are added, and soda solution is drop- 
ped in slowly from a burette until the color of the milk 
remains uniformly pinkish on agitation. 1 cc. of ^ alkali 

corresponds to .009 grams lactic acid, or to .045 per cent, 
when 20 cc. of milk are taken (see p. 112). 

B.— Cream, Skim milk, Butter milk. Whey, Con- 
densed MILK. 

259. The analysis of these products is conducted in 
the same manner as in case of whole milk, and the same 
constituents are determined, when a complete analysis is 
wanted. Skim milk, butter milk, and whey generally 



214 Testing Milk and Its Products. 

contain only small quantities of solids, and especially of 
fat, and it is, therefore, well to weigh out a larger quan- 
tity than in case of whole milk; if possible, toward 10 
grams. The acidity of sour milk and butter milk must 
be neutralized with sodium carbonate previous to the dry- 
ing and extraction, as lactic acid is soluble in ether and 
would thus tend to increase the ether- extract (fat), if not 
combined with an alkali previous to the extraction. 

260. Specific gravity of butter milk. The specific grav- 
ity of butter milk (as well as of sour or loppered milk) 
is determined by WeibulPs method; a known volume 
of the milk is mixed with a certain amount (say 10 per 
cent. ) of ammonia of a definite specific gravity, and the 
specific gravity of the liquid determined after thorough 
mixing and subsequent standing for an hour. If A desig- 
nate the volume of butter milk taken, B that of ammo- 
nia, and Othat of the mixture; and if furthermore *S de- 
signate the specific gravity of the butter milk, s^ that of 
the ammonia, and s^ that of the mixture, we have 

^- A ■ 

Klein ^ has modified this method by weighing the 
liquids, thus securing greater accuracy; 22 to 24 per 
cent. -ammonia is used, one tenth as much being taken as 
the amount of milk weighed out. The results come uni- 
formly .0005 too high, and this correction should always 
be made. The following formula will give the specific 
gravity of the milk, which in case of careful work will be 
accurate to one- half lactometer degree; if the letters given 
above designate weights (instead of volumes as before) 
and specific gravities of the liquids, respectively, we have 

'*- C B^ 

S2 Si 

.1 Milchzeitung, 1896, p. 656; see also De Koningh, Analyst, 1899, p. 142. 



Chemical Analysis of Milk and Its Products. 215 

261. Condensed milk. The same metliods are, in gen- 
eral, followed in the analysis of condensed milk as with 
whole milk. Condensed milk is preferably diluted with 
fi^e times its weight of water prior to the analysis, both 
because such a solution can be more easily handled 
than the undiluted thick condensed milk, and the errors 
of analysis are thereby reduced, and because the fat is 
not readily extracted except when the milk has been 
diluted. The same constituents are determined as in 
case of whole milk, viz., solids, fat, casein and albumen, 
ash, milk sugar, and cane sugar (if any has been added 
to the milk). The cane sugar is determined by the dif- 
ference between the solids not fat and the sum of the 
casein, albumen, milk sugar and ash; if the student has 
a knowledge of the manipulation of the polariscope and 
has had experience in gravimetric sugar analysis, the 
milk sugar is determined gravimetrically, and the cane 
sagar by the difference between the polariscope reading 
after inversion and the milk sugar present. 

The specific gravity of condensed milk may be determined 
by a method similar to that of McGill.^ 50 gr. of the 
thoroughly mixed sample are weighed into a tared beaker 
and washed with warm water into a 250 cc. flask, cooled 
to 60°, filled to the mark and carefully mixed. The 
specific gravity of this solution (a) is then taken and the 
original density is calculated by means of the following 
formula: 

Sp. gr. of condensed milk^-^^^^ 

Concentration. The extent of concentration of con- 
densed milk may be determined approximately by the 
formula devised by McGill (loc. cit. ): 



1 Bulletin 54, Laboratory Inland Rev. Dept., Ottawa, Canada. 



216 Testing Milk and Its Froduds. 

Concentration (c)=;^ 
where a and s designate the solids not fat and specific 
gravity, respectively, of the condensed milk, and a^ and 
Sj the corresponding data for the milk used. If s^ =1.030 
and rtj =9 per cent., then c=^ gives the concentration. 

C. — Butter. 

262. Sampling. A four- to eight-ounce sample of but- 
ter is melted in a tightly-closed pint fruit jar, shaken 
vigorously and cooled until the butter is hardened, the 
jar being shaken vigorously at short intervals during the 
cooling so as to keep the water of the butter evenly dis- 
tributed in the mass. 

263. a. Determination of water. Small pieces of but- 
ter (about 2 grams in all) are taken from the sample by 
means of a steel spatula and placed in glass tubes, seven- 
eighths of an inch in diameter and two and a half inches 
long, closed at the bottom by a layer, of stringy asbestos, 
and filled two-thirds full of asbestos prepared as for milk 
analysis (250). The tubes are dried at 100° C. in a water 
oven, until no further loss in weight takes place, and are 
then cooled and weighed. The loss in weight shows the 
per cent, of water present. 

264. b. Fat. The tubes are placed in Caldwell ex- 
tractors and extracted for four hours with anhydrous 
ether; the ether is then distilled off, and the flasks dried 
in the steam bath and weighed, the increase in weight 
giving the lat in the samples of butter weighed out. 

265. c. Casein. 10 grams of butter are weighed into 
a small beaker provided with a lip, and treated twice 
with about 50 cc. of gasoline each time; the solution is 



Cfiemical Analysis of Milk and Its Products. 217 

filtered off, and the residue transferred to a filter and 
dried; its nitrogen content is then determined by the 
Kjeldahl method (253). The nitrogen in the filter and 
the chemicals used is determined by blank trials and de- 
ducted. The nitrogen multiplied by 6.25 gives the 
casein in the butter. 

266. d. Ash. (1) 10 grams of butter are weighed into 
a porcelain dish and treated twice with gasoline, as in the 
preceding determination; the solution is filtered through 
an ash -free (quantitative) filter, and the filter when dry 
is transferred to the dish. The dish is heated in an air- 
bath for half an hour and then placed in a muffle oven, 
where the contents are burnt to a light greyish ash; the 
dish is now cooled in a desiccator and weighed. The 
difference between this weight and that of the empty dish 
gives the amount of ash in the butter weighed out. 

267. (2) About two grams of butter are weigbed into a 
small porcelain dish, half filled with stringy asbestos; the 
dish is dried for an hour in the water oven, and the fat 
then set fire to with a match, the asbestos fibre serving 
as a wick. When the flame has gone out, the dish is 
placed in a muffle oven, and the residue burnt to a grey- 
ish ash. After cooling, the dish is weighed, and the per 
cent, of ash in the butter calculated as under method 1. 

268. Complete analysis of butter in the same sample. 
About 2 grams of the butter are weighed into a platinum 
gooch half filled with stringy asbestos, and dried in a water 
oven at 100° C. to constant weight, cooled and weighed. 
The difference gives water in the sample. The gooch is 
then treated repeatedly with small portions of gasoline, 
suction being applied, and again dried in the water oven, 



218 Testing Milh and Its Products. 

cooled, and weighed; the fat in the sample is obtained 
from the difference between this and the preceding 
weight. The gooch is then carefully heated over direct 
flame until a light greyish ash is obtained; this operation 
is preferably done in a muffle oven to avoid a loss 
of alkali chlorids. The loss in weight gives the casein in 
the sample weighed out, and the increase in the weight 
of the gooch over that of the empty gooch with asbestos, 
gives the ash (mainly salt) of the butter. The salt in the 
ash may be dissolved out by hot water, and the chlorin 
content of the solution determined by means of a stand- 
ard silver-nitrate solution, using potassium chromate as 
an indicator. 

269. A practical method of estimating the salt content of 
butter. A method of estimating the salt content of butter, 
which is applicable also outside of chemical laboratories, has 
been worked out jointly by Messrs. Alfred Vivian and C. L- 
Fitch. 1 The salt of the butter is dissolved in hot water, and a 
certain portion of the solution when cool is pipetted off and 
titrated with a silver-nitrate solution prepared by dissolving 
one silver-nitrate tablet in 50 cc. water, potassium chromate 
being used as an indicator. The silver nitrate tablets are sold 
for 60 cents per 100, which number is sufficient to make 100-150 
tests. The method has been advertised in the dairy press under 
the name of "Fitch's Salt Analysis." Directions for making 
tests by this method are furnished with the apparatus when 
this is bought. The price of a complete outfit is $4.50. 

Detection of Artificial Butter. 

270. Determination of the specific gravity of the fil- 
tered butter fat serves as a good preliminary test. A 
number of practical methods for the detection of artifi- 
cial butter have been proposed, but they are either worth- 

1 Wis. Experiment Station, XVIl Report, pp. 98-JOl; Hoard's Dairy- 
man, February 15, 1901, " Uniform Salting of Butter." 



Chemical Analysis of Milk and Its Products. 219 

less, in case of samples containing a considerable propor- 
tion of natural butter, or give satisfactory results only in 
the hands of experts. The Eeichert-Wollny method given 
in detail below is the standard method the world over, 
and the results obtained by it are accepted in the courts. 

271. nitering the butter fat. The butter to be exam- 
ined is placed in a small narrow beaker and kept at 60° 
C. for about two hours. The clear supernatant fat is 
then filtered through absorbent cotton into a 200 cc. Erlen- 
meyer flask, taking care that none of the milky lower 
portion of the contents of the beaker be poured on the 
filter. In sampling the butter fat, it is poured back and 
forth repeatedly from a small warm beaker into the 
flask, and the quantity wanted is then drawn off with a 
warm pipette. 

272. Specific gravity. This is generally determined at 
100° 0. The method of procedure is similar to that de- 
scribed under milk (248). The picnometer (capacity 
about 25 cc. ) is filled with dry filtered butter fat, free 
from air bubbles; the fat is heated for 30 minutes in a 
beaker, the water in which is kept boiling. On cooling, 
the weight of picnometer and fafc is obtained, and by cal- 
culation as usual, the specific gravity of the fat. 

The specific gravity of pure natural butter fat at 100° C. 
ranges between .8650 and .8685, while artificial butter fat 
(i. e., fat from other sources than cows' milk) has a spe- 
cific gravity at 100° C. of below .8610, and generally 
about .85. 

273. Reichert-Wollny method {Volatile Acids). 5.75 cc. 
of fat are measured into a strong 250 cc. weighed saponi- 
fication flask, by means of a pipette marked to deliver 



220 Testing Milk and Its Products. 

this amount, and the flask when cool is weighed again. 
10 cc. of 95 per cent. -alcohol and 2 cc. of a concentrated 
soda solution (1:1) are then added to the flask which is 
securely stoppered with a cork stopper tied down with a 
piece of twine. The flask is heated for an hour on the 
water bath, being gently rotated from time to time in 
order to facilitate the saponification. The flask is then 
uncorked, the alcohol evaporated slt)wly and the heating 
continued until the last traces of alcohol are gone. 

100 cc. of recently boiled distilled water are now added, 
and the flask heated on the water bath until the soap 
formed is completely dissolved. When cooled to about 
70° C, 40 cc. of dilute sulfuric acid (25 cc. cone. H2SO4 
per liter) are added to the soap solution to decompose 
the soap into free fatty acids and glycerol. The flask is 
restoppered and heated until the insoluble fatty acids 
separated out form a clear oily layer on the surface of 
the acid solution in the flask. After cooling to room 
temperature, a few pieces of pumice stone (prepared by 
throwing the pieces at a white heat into distilled water 
and keeping them under water until used) are added, 
the flask connected with a glass condenser, heated slowly 
till boiling begins, and the contents then distilled at such 
a rate as will bring 110 cc. of the distillate over in as 
nearly thirty minutes as possible. 

The distillate is mixed thoroughly and filtered through 
a dry filter; 100 cc. of the filtrate are poured into a 250 cc. 
beaker and titrated with a deci-normal barium-hydrate 
solution, half a cubic centimeter of phenol phtalein solu- 
tion being used as an indicator. A blank test is made 
in the same manner as described, and the amount of 



Chemical Analysis of Milk and Its Products. 221 

alkali solution used deducted from the results obtained 
with the samples analyzed. The number of cubic centi- 
meters of barium-hydrate solution used is increased 
by one-tenth, and the so-called Reichert number thus 
obtained. 

The Reichert number for pure butter fat will ordinar- 
ily come above 24 cc ; butter fat from stripper cows will 
have a low Eeichert number. Pure oleomargarine will 
have a Eeichert number of 1-2 cc. ; and mixture of arti- 
ficial and natural butters will give intermediate numbers. 
Tests foic the Detection of Oleomargarine or 
Renovated Butter. 

274. The boiling test/ A piece of butter of the size of 
a small chestnut is melted in an ordinary tablespoon (or 
a small tin dish) at a low heat, stirring with a splioter 
of wood. The heat is increased until as brisk a boil as 
possible, and after boiling has begun, the melted mass is 
stirred thoroughly two or three times, always shortly 
before boiling ceases. Oleomargarine and renovated 
butter will boil noisily, sputtering like a mixture of 
grease and water when boiled, and will produce but 
little or no foam. Renovated butter produces usually a 
very small amount of foam, while genuine butter boils 
with less noise and produces an abundance of foam. 

274a. The Waterhouse test for distinguishing oleo- 
margarine and renovated butter.^ Half fill a 100 cc. 
beaker with sweet skim milk (or distilled water), heat 



1 Patrick, Household tests for the detection of oleomargarine and reno- 
vated butter, Farmers' Bulletin, No. 131. For detection and exa nination 
of renovated or "process" butter, see also Cochran, Journl. Frankl. Inst., 
1899, p. 94 ; Analyst, 1899, p. 88. 

2 Farmers' Bulletin, No, 131, p. 7. 



222 Testifig Milk and Its Products. 

nearly to boiliDg and add 5 to 10 grams of butter or 
oleomargarine. Stir with a small wooden stick of about 
the size of a match until the fat is melted; the beaker is 
then placed in ice water, and the milk (or water) stirred 
until the temperature falls sufficiently for the fat to 
congeal. If oleomargarine, the fat can now be easily 
collected into one lump by means of the stick, while if 
genuine or renovated butter, the fat will granulate and 
can not be so collected. 

D. — Cheese. 

For method of sampling, see p. 89. 

275. a. Water. Five grams of cheese cut into very 
thin slices are weighed ipto a small porcelain dish filled 
about one-third full with freshly-ignited stringy asbestos; 
the dish is placed in a water oven and heated for ten 
hours. The loss in weight is taken to represent water. 

276. b. Fat. About 5 grams of cheese are ground 
finely in a small porcelain mortar with about twice its 
weight of anhydrous copper sulfate, until the mixture is 
of a uniform light blue color and the cheese evenly dis- 
tributed throughout the mass. The mixture is trans- 
ferred to a glass tube of the kind used in butter analysis 
(263), only a larger size; a little copper sulfate is placed 
at the bottom of the tube, then the mixture containing 
the cheese, and on top of it a little extracted absorbent 
cotton or ignited stringy asbestos; the tube is placed in 
an extraction apparatus and extracted with anhydrous 
ether for fifteen hours. The ether is then distilled off, 
the flasks dried in a water oven at 100° C. to constant 
weight, "cooled and weighed. The method is apt to give 



GhemicaU Analysis of Milk and Its Products. 223 

too low results and, therefore, not to be preferred to the 
Babcock test for cheese (102). 

277. c. Casein (total nitrogen x 6.25). About 2 grams 
of cheese are weighed out on a watch glass and trans- 
ferred to a Jena nitrogen flask, and the nitrogen in the 
sample determined according to the Kjeldahl method 
(253); the percentage of nitrogen multiplied by 6.25 
gives the total nitrogenous components of the cheese. 

278. d. Ash. -The residue from the water determina- 
tion is taken for the ash; it is preferably set fire to, in 
the same manner as explained under determination of 
ash in butter (267), before it is placed in the muffie oven 
and incinerated. The increase in the weight above that 
of the empty dish+asbestos, gives the amount of ash in 
the sample weighed out. 

279. e. Other constituents. The sum of the percent- 
ages of water, fat, casein and ash, subtracted from 100, 
will give the per cent, of other constituents, organic 
acids, milk sugar, etc., in the cheese. 

Detection of Oleomaegarine Cheese (^'Filled" 
Cheese). 

280. About 25 grams of finely-divided cheese are 
extracted with ether in a Caldwell extractor or a paper 
extraction cartridge; the ether is distilled off, and the 
fat dried in the water oven until there is no further loss 
in weight. 5.75 cc. of the clear fat are then measured 
into a 250 cc. saponification flask and treated according 
to the Eeichert-Wollny method, as already explained 
under Detection of Ay^tifcial Butter (270).^ 



1 See Arb. Kais. Ges.-Amt., 14, 506- 



224 Testing Milk and Its Products.* 

Tests for Adulteration of Milk and Cream. 

281. The nitric acid test may prove useful as corrobora- 
tive evidence that a sample of milk has been watered 
(123). Normal fresh milk does not contain nitrates, 
while common well-water, particularly on farms where 
precautions to guard against contamination of the water 
supply have not been taken, in general contains appreci- 
able amounts of nitrates, nitrites and ammonia com- 
pounds, and wa^^ered milk will, therefore, in such cases 
also contain nitrates.^ The method for detection of small 
amounts of nitrates in milk, as given by Eichmond^ is 
as follows: Place a small quantity of diphenylamin at 
the bottom of a porcelain dish, and add to it about 1 cc. 
of pure HjSO^ (cone); allow a few drops of the milk 
serum (obtained by adding a little acetic acid to the milk 
and warming) to flow down the sides of the dish and 
over the surface of the acid. If a blue color developes 
in the course of ten minutes, though it may be faint, it 
shows the presence of nitrates, after ten minutes a red- 
dish-brown tolor is always developed from the action of 
the acid on the serum. There should be no difficulty in 
detecting an addition of 10 per ct. of water to the milk 
by this test, if the water added contained 5 parts of nitric 
acid, or more, per 100,000. 

Besides by the methods given in the preceding (pp. 
101-107), watering or skimming of milk may be detected 
by determining the specific gravity of «, the skim milk, 
6, the milk serum, and c, the whey. 



1 Uffelmann, Deutsche Vierteljahresschr. f. off. Ges.-pfl. 15, p. 

2 The Analyst, 1893, p. 272. 



Chemical Analysis of Milk and Its Products. 225 

282. a. Specific gravity of skim milk. The milk is set 
in a flat porcelain or glass dish for 12-24 hours in a cold 
room; the layer of cream formed is then skimmed off, 
and the sp. gr. of the skim milk determined at 60° F. 
Skim milk has a sp. gr. of .002 to .0035 (2 to 3.5 lactom- 
eter degrees) above that of the corresponding whole 
milk; a smaller difference than this indicaies that the 
milk was skimmed. If both skimming and watering had 
been practiced, the difference given above might be ob- 
tained, but the analysis of the milk would in such case 
easily disclose the adulteration. 

283. Specific gravity of the milk serum. To 100 cc. 
milk 2 cc. of 20 per ct. -acetic acid are added, and the 
mixture heated in a covered beaker or closed flask for 
5-10 min. on a water-bath at 55-65° C. After cooling, 
the milk serum is filtered off and its sp. gr. determined 
at 60° F. In case of pure milks, the sp. gr. of the milk 
serum (at 60°) will come above 1.0270. Serum from 
normal milks contain 6.3 to 7.5 per ct. solids and .22 
to .28 per ct. fat; by the addition of 10 per ct. of water, 
the solids in the serum are lowered .3 to .5 per ct., and 
thesp. gr., .0005.^ 

c. Specific gravity of whey. 500 cc. of milk are warmed 
in water of 40-50° 0. until its temperature is 35° 0. ; 
one-half cc. of rennet extract (12-15 drops) is added, 
and the milk stirred thoroughly. After allowing the 
curd to solidify for 10 minutes, it is cut and the whey 
filtered off through several layers of cheese cloth. The 
whey must be clear; it is cooled to 15° 0. and its sp. gr. 
determined. The sp. gr. of whey from normal milk ob- 



1 Koaig, Menschl. Nahrungsmittel, II, p. 276. 
15 



226 Testing Milk and Its Products. 

tained in the manner given will range between 1,027 
and 1.031. A sp. gr. of 1.026 or below indicates water- 
ing. An addition of 4 per ct. of water lowers the sp. gr. 
of the whey about 1 lactometer degree.^ 

284. Detection of coloring matter. Milk which has 
been watered or skimmed, or both, is sometimes further 
adulterated by unscrupulous milk dealers by an .ad- 
dition of a small quantity of cheese color; this will 
mix thoroughly with the milk, and, if added judiciously, 
will impart a rich cream color to it. The presence of 
foreign coloring matter in milk is easily shown by shak- 
ing 10 cc. of the milk with an equal quantity of ether; 
on standing, a clear ether solution will rise to the surface; 
if artificial coloring matter has been added to the milk, 
the solution will be yellow colored, the intensity of the 
color indicating the quantity added; natural fresh milk 
will give a colorless ether solution. 

A method given by Wallace' is claimed to detect one 
part of coloring matter in 100,000 of milk. 

Inorganic coloring matter like chromates and bi-chro- 
mates have, although fortunately rarely, been used to 
impart a rich color to adulterated milk or poor cream. 
Chromates may be detected by the reddish yellow color 
produced when a little 2 per cent. -silver nitrate solution 
is added to a few cubic centimeters of the milk. 

285. Detection of pasteurized milk or cream. Prof. 
Storch, of Copenhagen, Denmark,^ in 1898, published a 
simple method for ascertaining whether milk, cream, 
butter or other dairy products have been heated to at 
least 176° F. (80° C). The test is made as follows: A 
teaspoonful of the milk is poured into a test tube, and 

1 Siats, Unters. landw. wicht. Stoflfe, p. 88. 

2 N. J. Dairy Commissioner, report. 1896, p. 36. 

3 40th report, Copenhagen experiment station. 



Chemical Analysis of Milk and Its Products. 227 

1 drop of a weak solution of peroxid of hydrogen (2 per 
cent.) and 2 drops of a paraphenylenediamin- solution 
(2 per cent.) are added. The mixture is then shaken; 
if a dark violet color appears at once, the milk has not 
been heated, or at any rate not beyond 176° F. If a 
sample of butter is to be examined, 25 grams are placed 
in a small beaker and melted by being placed in water 
of 60° 0. The clear butter fat is poured off, and the 
remaining liquid is, diluted with an equal volume of 
water. The mixture thus obtained is examined as in 
case of milk. 

286. Boiled milk. The preceding test will serve to 
distinguish between raw and boiled milk, and also to 
ascertain if milk has been adulterated with diluted con- 
densed milk. To what extent such an adulteration can 
be practiced without being detected by this or similar 
tests, has not been determined, but if a control test be 
made at the same time with a sample of milk of known 
purity, a small admixture of boiled (or diluted con- 
densed) milk can doubtless be detected.^ 

287. Gelatine in cream. This method of adulteration 
is sometimes practiced in the city cream trade, to impart 
stiffness and an appearance of richness to the cream. To 
detect the gelatine, a quantity of the suspected cream is 
mixed with warm water, and acetic acid is added to 
precipitate the casein and fat (1.5 cc. of 10 per cent.- 
acetic acid per 10 cc. of cream is sufficient). The pre- 
cipitate is filtered off, and a few drops of a strong tannin 
solution are added to the clear filtrate. Pure cream will 
give a slight precipitate, while in the presence of gela- 
tine a copious precipitate will come down. 



1 See also Siats, Unters. landw. wicht. Stoffe, p. 60, and Molkerei-Ztg. 
(Hildesheim), 1899. p. 677. 



228 Testing Milk and Its Products. 

The picric-acid method has also been proposed for the 
detection of small quantities of gelatine in cream/ 

288. Starch in cream. Starch is mentioned in the dairy 
literature as an adulterant of milk and cream. It is 
doubtful, however, if it is ever used for this purpose at 
the present time. In the case of ice-cream, on the other 
hand, a small quantity of corn starch is often added to 
thicken the milk used. It may in such a case be readily 
detected by means of the iodin reaction. A solution of 
iodin will produce a deep blue color in the presence of 
starch; a small amount of iodin is taken up by the cream 
before the blue coloration appears. 

289. Macroscopic impurities (particles of hay, litter, 
woolen or cotton fibres, dung, etc.) These impurities 
may be separated by repeated dilution of the milk with 
pure distilled water, leaving the mixture undisturbed 
for a couple of hours each time before the liquid is 
syphoned off. When the milk has been entirely removed 
in this manner, the residue is filtered off, dried and 
weighed. A quart of milk or cream should not give any 
visible sediment on standing for several hours. 

Detection oe Preseeyatives in Dairy Products. 

290. a. Boracic acid (borax, borates, preservaline, etc.),^ 
100 cc. of milk are made alkaline with a soda or potash 
solution, and then evaporated to dryness and incinerated. 
The ash is dissolved in water to which a little hydro- 
chloric acid has been added, and the solution filtered. 
A strip 01 turmeric paper moistened with the filtrate will 
be colored reddish brown when dried at 100° 0. on a 
watch glass, if boracic acid is present. 

If a little alcohol is poured over the ash to which con- 
centrated sulfuric acid has been added, and fire is set to 



1 The Analyst, 1897, p. 320. 



chemical Analysis of Milk and Its Products. 229 

the alcohol after a little while, it will burn with a yel- 
lowish green tint, especially noticeable if the ash is 
stirred with a glass rod and when the flame is about to 
go out. 

29 r. The following modification of the first test given is said 
to show the presence of only a thousandth of a grain of borax 
in a drop of milk (about .15 per cent. ) :^ 

Place in a porcelain dish one drop of milk with two drops of 
strong hydrochloric acid and two drops of saturated turmeric 
tincture; dry this on the water bath, cool and add a drop of 
ammonia by means of a glass rod. A slaty blue color changing 
to green is produced if borax is present.'^ 

292. b. Bi-Carbonate of soda. 100 cc. of milk to which 
a few drops of alcohol are added, are evaporated and 
carefully incinerated j the proportion of carbonic acid in 
the ash as compared with that of milk of known purity 
is determined. If an apparatus for the determination of 
carbonic acid is available, like the Scheibler apparatus, 
etc., the per cent, of carbonic acid per gram of ash (and 
quart of milk) can be easily ascertained. Normal milk 
ash contains only a small amount of carbonic acid (less 
than 2 per cent. ), presumably formed from the citric acid 
of the milk in the process of incineration. 

The following qualitative test is easily made: To 10 cc. 
of milk add 10 cc. of alcohol and a little of a one per cent, 
rosolic-acid solution. Pure milk will give a brownish 
yellow color; milk to which soda has been added, a rose 
red color. A control experiment with milk of known 
purity should be made. 

293. c. riuroids. 100 cc. of milk are evaporated in a 
platinum or lead crucible, and incinerated; the ash is 
made strongly acid with concentrated sulfuric acid. If 
fluroids are present, hydrofluoric acid will be generated 

1 N. J. Dairy Commissioner, report 1896, p. 37. 

2 See also 139, 144. 



230 Testing Milk and Its Products. 

on gentle heating and will be apparent from its etching 
a watch glass placed over the crucible. ^ 

294. d. Salicylic acid {salicylates^ etc.). 20 cc. of milk 
are acidulated with sulfuric acid and shaken with ether; 
the ether solution is evaporated, and the residue treated 
with alcohol and a little iron-chlorid solution; a deep 
violet color will be obtained in the presence of salicylic 
acid. 

295. e. Formaldehyde (a forty-per cent, solution in 
water). A solution of diphenylamin is made with water 
and just enough sulfuric acid to dissolve it. The milk 
to be tested, or better, the distillate therefrom, is added 
to this solution and boiled. If formalin be present, a 
white flocculent precipitate is formed; if the acid used 
contained nitrates, a green precipitate will be formed. 

The following method by Hehner is stated to show the 
presence of 1 part of formaldehyde in 200,000 parts of 
milk : the milk is diluted with an equal volume of water, 
and strong H^^SO^ (sp. gr. 1.82-1.84) is added. A vio- 
let ring is formed at the junction of the two liquids if 
formaldehyde is present; if not, a slight greenish tinge 
will be seen. The violet color is not obtained with milks 
containing over .05 per cent, formaldehyde. ^ 

An adulteration of milk with formaldehyde may be 
readily detected by the following method, which will 
show the presence of only a trace of formaldehyde in the 
milk. 5 cc. of milk is measured into a white porcelain 
dish, and a similar quantity of water added. 10 cc. of 
HCl containing a trace of FCgOlg is added, and the 
mixture is heated very slowly. If formaldehyde is pres- 
ent, a violet color will be formed. 

1 Chromates in dairy products may be readily determined by the use of 
a silver-nitrate solution, see Molkerei Ztg. (Ber in) 1899, p. 603. 

2 Chem. News, 1896, No. 71; Milchzeitung, 1896, 491; 1897, 40, 667; The An- 
alyst, 1895, 152, 154, 157; 1896, 285. 



GOyEE:N^MENT STAND AEDS OF PUEITY FOE 
MILK AND ITS PEODUCTS. 



a. MILK. 

Definition. 1. Milk [whole milk) is the lacteal secretion ob- 
tained by the complete milking of one or more healthy cows, 
properly fed and kept, excluding that obtained within fifteen 
days before and five days after calving. 

Standard, standard milk is milk containing not less than 
twelve (12) per cent, of total solids and not less than eight and 
one half (8.5) per cent, of solids not fat, nor less than three 
and one-quarter (3.25) per cent, of milk fat. 

Definitions. 2. Blended milk is milk modified in its composi- 
tion so as to have a definite and stated percentage of one or 
more of its constituents. 

3. Skim, m.ilk is milk from which a part or all of the cream 
has been removed. 

Standard. Standard skim, tnilk is skim milk containing not 
less than nine and one-quarter (9.25) per cent, of milk solids. 

4. Buttermilk is the product that remains when butter is 
removed from milk or cream in the process of churning. 

5. Pasteurized milk is standard milk that has been heated 
below boiling but sufficiently to kill most of the active organ- 
isms present and immediately cooled to fifty degrees (50°) Fahr. 
or lower to retard the development of their spores. 

6. Sterilized m,ilk is standard milk that has been. heated at 
the temperature of boiling water or higher for a length of time 
sufficient to kill all organisms present. 

7. Condensed milk is milk from which a considerable por- 
tion of water has been evaporated. 

8. Sweetened Condensed milk is milk from which a consider- 
able portion of water has been evaporated and to which sugar 
(sucrose) has been added. 

Standard. Standard condetised milk and standard sweetened 
condensed milk are condensed milk and sweeteued condensed 
milk, respectively, containing not less than twenty-eight (28) 
per cent of milk solids, of which not less than one-fourth is 
milk fat. 

9. Condensed skim milk is skim milk from which a consider- 
able portion of water has been evaporated. 

b. MILiK FAT OR BUTTER FAT. 

Definition. 1. Milk fat or butter fat is the fat of milk. 

Standard. Standard milk fat or butter fat has a Eeichert- 
Meissl number not less than twenty-four (24) and a specific 
gravity not less than 0.905 (40° C. /*40° C. ). 



1 Circular No. 10, Office of the Secretary, U. S. Dept. Agriculture, Nov. 



232 Testing Milk and Its Products. 

C. CREAM. 

Definition. 1. Oeam is that portion of milk, rich in butter fat, 
which rises to the surface of milk on standing, or is separated 
from it by centrifugal force. 

Standard. Standard cream is cream containing not less 
than eighteen (18) per cent, of milk fat. 

2. Evaporated cream, is cream from which a considerable 
portion of water has been evaporated. 

d. BUTTER. 

Definition. 1. Butter is the product obtained by gathering in 
any manner the fat of fresh or ripened milk or cream into a 
mass, which also contains a small portion of the other milk 
constituents, with or without salt. By acts of Congress ap- 
proved August 2d, 1886, and May 9th, 1902, butter may also con- 
tain additional coloring matter. 

Standard. Standard butter is butter containing not less than 
eighty- two and five- tenths (82.5) per cent, of butter fat. 

Definition. 2. Renovated or process butter is the product ob- 
tained by melting butter and reworking, without the addition 
or use of chemicals or any substances except milk, cream, or 
salt. 

Standard. Standard renovated or process butter is renovated 
or process butter containing not more than sixteen (16) per 
cent, of water and at least eighty-two and five- tenths (82.5) per 
cent, of butter fat. 

e. CHEESE. 

Definitions. 1. Cheese is the solid and ripened product obtained 
by coagulating the casein of milk by means of rennet or acids, 
with or without the addition of ripening ferments and season- 
ing. By act of Congress, approved June 6, 1896, cheese may 
also contain additional coloring matter. 

2. Whole-milk or full-cream cheese is cheese made from milk 
from which no portion of the fat has been removed. 

3. Cream cheese is cheese made from milk and cream, or 
milk containing not less than six (6) per cent, of fat. 

Standard. Standard whole-milk cheese or full-cream cheese is 
whole-milk or full-cream cheese containing in the water-free 
substance, not less than fifty (50) per cent, of butter fat. 

f. MISCELLANEOUS MILK PRODUCTS. 

Definitions. 1. Whey is the product remaining after removal 
of fat and casein from milk in the process of cheese making. 

2. Kumiss is mare's or cow's milk, with or without the 
addition of sugar (sucrose), which has undergone alcoholic 
fermentation. 



APPENDIX. 



Table I. Composition of milk and its products. 



Cows' milk. 



Colostrum milk 

Cream. 

Cream, Cooley 

Skim milk (gravity). 

Skim milk (Centrifugal). 
Buttermilk 



Whey 



Condensed milk, 

(no sugar added)... 
Condensed milk, 

(sugar added) 

Butter, salted 

" sweet cream 

" sour cream 

" unsalted 

" World's Fair, 1893..... 
Cheese, cream 

" full cream 

" Cheddar, green 

" Cheddar, cured 

" World's Fair 
Mam'th, 1893 

" half-skim 

** skim 

" centrifugal skim 



No. of 
analyses, 



793 



5,552 

2,173 

200,000 

42 

43 

203 

56 

354 



36 

64 

,676 

10 

11 

242 

350 

.127 

143 



Water 



Fat. 



58.99 

25.61 
11.95 
12.93 
13.08 
13.0 
1.57 
36.33 
38.00 
36.84 
34.38 

32.06 
39.79 
46.00 
50.5 



12.42 



34.43 

23.92 

11.65 

1.2 



Casein 

and 

alb ' men 



pr. ct. 

3.55 
3.50 
3.20 
3.512 
3.40 
17.64 
3.76 



3.26 



3.55 
4.03 



.81 
11.92 



11 



Milk 
sugar. 



pr. ct 

4.88 
4.6U 
5.10 



4.75 
2.67 
4.23 



4.74 



5.25 
4.04 



4.79 
5. 

14.49 



Ash. 



pr ct. 

.71 

.75 
.70 

^71 
.75 

1.56 
.53 
.62 
.7 



Authority. 



,72 



.65 



79 
1.26 

61 I 
81 

1.57 
.95 
84 
35 
72 
38 



50.06 



28.00 
29.67 
34.06 
43.1 



2.18 

2.19 
2.58 
1.25 
1.19 
.12 
2.7 
3.10 
4.97 



1,02 
1.43 

5.61 
2.95| 3.58 



5.51 



1.79 
3.42 



4.73 

4.87 
5.2 



Konig.5 
Fleischmann. 
Van Slyke. 
Holland. 6 
Richmond. 
Konig.^ 
(( 

Holland. « 
Konig.5 
Holland. « 
Van Slyke. 
Konig.^ 
Holland. « 
Konig.^ 
Van Slyke. 

Konig.^ 



Woll. 

Konig.5 

u 

Woll. 

Farrington. 

Konig.^ 

Van Slyke. 
Drew. 

Shutt. 
Konig.5 

u 

Storch. 



1 70 per cent, of this amount is albumen. 

2 Forty-two analyses. 

3 Eiglit analyses. 



413.60 percent, albumen. 
6 Mostly European samples. 
6 Massachusetts' samples. 



234 



Testing Milk and Its Products. 



9 

2 

a 
"5 

u 
.© 



n 

e 

s 

(A 

c 

(0 

I 

C/D 





~ 










"V 




















s5^ 


total sol. to be fat 

total sol. to be fat 

milk testing a 
t3 perct. fat. 




i 


£ 


i.a1 


C 








a ft II 




p^ 






: ?"So^ 










1 




: ^ ^ ^ >H « 
: o **rf . 
t "^ 






s 


5 




o : 


:a 2 ?, 






H J 


3| 


jv : 


•CO 
•OS 














« ! 


: lO lO t^ 


Ut) 








S 


^ i 


: CO CO CO CO CO CO CO 


CO 




coco 


. 


"(O '. 












^'i 


o 




1 — 1 






M 




'.a • Lc o • lo 


lO 




c: C5 


J 


n 


1^ • 


OC • -Ol 05 • 








y 


^ ! 


: O Oi Oi 


C5 






^ 




1 — 1 








. 






o 




i-s 


o : 


: "• ■'M^M CC C-l 'Tl ''^oiCO 




CO 01 or-M —I 




5i 


^ i 


\^ i "^""5-2" 










" : 


: '^ 














t) 








. r^ 






• -t-J 
























: r. 






kO) : 




"^ 








: o 






1 U 










c 






d 


^ o 






s J. - i! 






C3 






<2 






1"^^ si 








3 


u 1 


c 


^ 






'i 


\i 








1 



Appendix. 



235 






1^^ -s 



sxi ftd «d u^ 

^H O O 02 



J? a 

P !=l P 









ftll fH § £ bCcIl 
,^ Ol Q "^ .CO 



N to 






'SIX' 






I — I lO 

C5 GO ai 



COr-l 



I — iiO 



o 



I 

p-l 



- 03 

^ o 

"Sill 






»ooo 



CO •^* (M* CO 



o c ooooo 
cq CO cq" cq" (:>q oq (?q 



CO -^§G^ 



-d : 






irj S S 



.5 O c3 K. rM o3 ^ 
• S 'S -2 § '^ d ^ 

O O 

S >.- :. ^ - - ^ 



o 
o 



O 



: X! o) 

^ fe o £ 



is 
fcca 



fl fl ''J 9 

•2,2cq o 
o o O PI 

rS i '-I «* 

'O o o e 

l» g CO 



236 



Testing Milk and Its Products. 



Table III. Quevenne lactometer degrees corresponding to 
N. Y. Board of Health degrees. (See p. 97. ) 



Bd. of Health 


Quevenne 


Bd. of Health 


Quevenne 


Bd. of Health 


Quevenne 


degrees. 


scale. 


degrees. 


scale. 


degrees. 


scale. 


60 


17.4 


81 


23.5 


101 


29.3 


61 


17.7 


82 


23.8 


102 


29.6 


62 


18.0 


83 


24.1 


103 


29.9 


63 


18.3 


84 


24.4 


104 


30.2 


64 


18.6 


85 


24.6 


105 


30.5 


65 


18.8 


86 


24.9 


106 


30.7 


66 


19.1 


87 


25.2 


107 


31.0 


67 


19.4 


88 


25.5 


108 


31.3 


68 


19.7 


89 


25.8 


109 


31.6 


69 


20.0 


90 


26.1 


110 


31.9 


70 


20.3 


91 


26.4 


' 111 


32.2 


71 


20.6 


92 


26.7 


112 


32.5 


72 


20.9 


93 


27.0 


113 


32.8 


73 


21.2 


94 


27.3 


114 


33.1 


74 


21.5 


95 


27.6 


115 


33.4 


75 


21.7 


96 


27.8 


116 


33.6 


76 


22.0 


97 


28.1 


117 


33.9 


77 


22.3 


98 


28.4 


118 


34.2 


78 


22.6 


99 


28.7 


119 


34.5 


79 


22.9 


100 


29.0 


120 


34.8 


80 


23.2 











Table IV. Value of 



100 s— 100 



for sp. gr. from 1.019 to 1.0369. 



Sp.gr. (s) = 


0.0000 


0.0001 


0.0002 


0.0003 


0.0004 


0.0005 


0.0006 


0.0007 


0.0008 


0.0009 


1.019 


1.864 


1.874 


1.884 


1.894 


1.903 


1.913 


1.922 


1.932 


1.941 


1.951 


1.020 


1.961 


1.970 


1.980 


1.990 


1.999 


2.009 


2.018 


2.028 


2.038 


2.047 


1.021 


2.057 


2.066 


2.076 


2.086 


2.095 


2.105 


2.114 


2.124 


2.133 


2.143 


1.022 


2.153 


2.162 


2.172 


2.181 


2.191 


2.200 


2.210 


2.220 


2.229 


2.239 


1.023 


2.249 


2.258 


2.267 


2.277 


2.2S6 


2.296 


2.306 


2.315 


2.325 


2.334 


1.024 


2.344 


2.353 


2.363 


2.372 


2.382 


2.391 


2.401 


2.410 


2.420 


2.430 


1.025 


2.439 


2.449 


2.458 


2.468 


2.477 


2.487 


2.496 


2.506 


2.515 


2.525 


1.026 


2.534 


2.544 


2.553 


2.563 


2.573 


2.582 


2.591 


2.601 


2.610 


2.620 


1.027 


2.629 


2.638 


2.648 


2.657 


2.667 


2.676 


2.686 


2.695 


2.705 


2.714 


L028 


2.724 


2.733 


2.743 


2.752 


2.762 


2.771 


2.781 


2.790 


2.799 


2.809 


1.029 


2.818 


2.828 


2.837 


2.847 


2.S56 


2.865 


2.875 


2.884 


2.893 


2.903 


1.030 


2.913 


2.922 


2.931 


2.941 


2.951 


2.960 


2.969 


2.979 


2.988 


2.997 


1.031 


3.007 


3.016 


3.026 


3.035 


3.044 


3.054 


3.063 


3.072 


3.082 


3.091 


1.032 


3.101 


3.110 


3.120 


3.129 


3.138 


3.148 


3.157 


3.106 


3.176 


3.185 


1.033 


3.195 


3.204 


3.213 


3.223 


3.232 


3.241 


3.251 


3.260 


3.269 


3.279 


1.034 


3.288 


3.298 


3.307 


3.316 


3.326 


3.335 


3.344 


3.354 


3.363 


3.372 


1.085 


3.382 


3.391 


3.400 


3.410 


3.419 


3.428 


3.438 


3.447 


3.456 


3.466 


1.036 


3.475 


3.484 


3.494 


3.503 


3.512 


3.521 


3.531 


3.540 


3.549 


3.559 



[See directions for use, p. 105). 



Appendix. 237 

Table V» Correction-table for specific gravity of milk. 



h 
If 




Temperatu 


re of milk (in degrees Fahrenheit). 


51 


52 


53 


54 


55 


56 


57 


53 


59 


60 


20 


19.3 


19.4 


19.4 


19.5 


19.6 


19.7 


19.8 


19.9 


19.9 


20.0 


21 


20.3 


20.3 


20.4 


20.5 


20.6 


20.7 


20.8 


20.9 


20.9 


21.0 


22 


21.3 


21.3 


21.4 


21.5 


21.6 


21.7 


21.8 


21.9 


21.9 


22.0 


23 


22.3 


22.3 


22.4 


22.5 


22.6 


22.7 


22.8 


22.8 


22.9 


23.0 


24 


23.3 


23.3 


23.4 


23.5 


2:^>.6 


23.6 


23.7 


23.8 


23.9 


24.0 


25 


24.2 


24.3 


24.4 


24.5 


24.6 


24.6 


24.7 


24.8 


24.9 


25.0 


26 


25.2 


25.2 


25.3 


25.4 


25.5 


25.6 


25.7 


25.8 


25.9 


1^6.0 


27 


26.2 


26.2 


26.3 


26.4 


26.5 


26.6 


26.7 


26.8 


26.9 


27.0 


28 


27.1 


27.2 


27.3 


27.4 


27.5 


27.6 


27.7 


27.8 


27.9 


28.0 


29 


28.1 


28.2 


28.3 


28.4 


28.5 


28.6 


28.7 


28.8 


28.9 


29.0 


30 


29.1 


29.1 


29.2 


29.3 


29.4 


29.6 


29.7 


29.8 


29.9 


30.0 


31 


30.0 


30.1 


30.2 


30.3 


30.4 


30.5 


30.6 


20.8 


30.9 


31.0 


32 


31.0 


31.1 


31.2 


31.3 


31.4 


31.5 


31.6 


31.7 


31.9 


32.0 


33 


31.9 


32.0 


32.1 


32.3 


3-2.4 


32.5 


32.6 


32.7 


32.9 


33.0 


34 


32.9 


33.0 


33.1 


33.2 


33.3 


33.5 


33.6 


33.7 


33.9 


34.0 


35 


33.8 


33.9 


34.0 


34.2 


34.3 


34.5 


34.6 


34.7 


34.9 


35.0 




61 


62 


63 


64 


65 


66 


67 


68 


69 


70 


20 


20.1 


20.2 


20.2 


20.3 


20.4 


20.5 


20.6 


20.7 


20.9 


21.0 


21 


21.1 


21.2 


21.3 


21.4 


21.5 


21.6 


21.7 


21.8 


22.0 


22.1 


22 


22.1 


22.2 


22.3 


22.4 


22.5 


22.6 


22.7 


22.8 


23.0 


23.1 


23 


23.1 


23.2 


23.3 


23.4 


23.5 


23.6 


23.7 


23.8 


24.0 


24.1 


24 


24.1 


24.2 


24.3 


24.4 


24.5 


24.6 


24.7 


24.9 


25.0 


25.1 


25 


25.1 


25.2 


25.3 


25.4 


25.5 


25.6 


25.7 


25.9 


26.0 


26.1 


26 


26.1 


26.2 


26.3 


26.5 


26.6 


26.7 


26.8 


27.0 


27.1 


27.2 


27 


27.1 


27.3 


27.4 


27.5 


27.6 


27.7 


27.8 


28.0 


28.1 


28.2 


28 


28.1 


28.3 


28.4 


28.5 


28.6 


28.7 


28.8 


29.0 


29.1 


29.2 


29 


29.1 


29.3 


29.4 


29.5 


29.6 


29.7 


29.9 


30.1 


30.2 


30.3 


30 


30.1 


30.3 


30. .4 


30.5 


30.7 


30.8 


30.9 


31.1 


31.2 


31.3 


31 


31.2 


31.3 


31.4 


31.5 


31.7 


31.8 


31.9 


32.1 


32.2 


32.4 


32 


32.2 


32.3 


32.5 


32.6 


32.7 


32.9 


33.0 


33.!: 


33.3 


33.4 


33 


33.2 


33.3 


33.5 


33.6 


33.8 


33.9 


34.0 


34.2 


34.3 


34.5 


34 


34.2 


34.3 


34.5 


34.6 


34.8 


34.9 


35.0 


35.2 


35.3 


35.5 


35 


35.2 


35 .'3 


35.5 


35.6 


35.8 


35.9 


36.1 


36.2 


36.4 


36.5- 



DiRECTiOKS.— Bring the temperature of the milli to within 10° of 
60° F. Take the reading of the lactometer and that of the temperature of 
the milk; find the former in the first vertical column of the table and the 
latter in the first horizontal row of figures; the figure where the horizontal 
and vertical columns meet is the corrected lactometer reading; e.g., ob- 
served, 31.0 at 67° F. ; corrected reading, 31.9. 



238 



Testing Milk and Its Products. 



Table VI. Per cent, of solids not fat, corresponding to to 
6 per cent, of fat, and lactometer readings of 26 to 

36. (See directions for use, p. 100. ) 



O 

*3 


Lactometer readings at 60° P. 




is 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 







6.50 


6.75 


7.00 


7.25 


7.50 


7.75 


8.00 


8.25 


8.50 


8.75 


9.00 





0.1 


6.52 


6.77 


7.02 


7.27 


7.52 


/.77 


8.02 


8.27 


8.52 


8.77 


9.02 


0.1 


0.2 


6.54 


6.79 


7.04 


7.29 


7.54 


7.79 


8.04 


8.29 


8.54 


8.79 


9.04 


0.2 


0.3 


6.56 


6.81 


7.06 


7.31 


7.56 


7.81 


8.06 


8.31 


8.56 


8.81 


9.06 


0.3 


0.4 


6.68 


6.83 


7.08 


7.33 


7.58 


7.83 


8.08 


8.33 


8.58 


8.83 


9.08 


0.4 


0.5 


6.60 


6.85 


7.10 


7.35 


7.60 


7.85 


8.10 


8.35 


8.60 


8.85 


9.10 


0.5 


0.6 


6.62 


6.87 


7.12 


7.37 


7.62 


7.87 


8.12 


8.37 


8.62 


8.87 


9.12 


0.6 


0.7 


6.64 


6.89 


7.14 


7.39 


7.64 


7.89 


8.14 


8.39 


8.64 


8.89 


9.14 


0.7 


0.8 


6.66 


6.91 


7.16 


7.41 


7.66 


7.91 


8.16 


8.41 


8.66 


8.91 


9.16 


0.8 


0.9 


6.68 


6.93 


7.18 


7.43 


7.68 


7.93 


8.18 


8.43 


8.68 


8.93 


9.18 


0.9 


1.0 


6.70 


6.95 


7.20 


7.45 


7.70 


7.95 


8.20 


8.45 


8.70 


8.95 


9.20 


1.0 


1.1 


6.72 


6.97 


7.22 


7.47 


7.72 


7.97 


8.22 


8.47 


8.72 


8.97 


9.22 


1.1 


1.2 


6.74 


6.99 


7.24 


7.49 


7.74 


7.99 


8.24 


8.49 


8.74 


8.99 


9.24 


1.2 


1.3 


6.76 


7.01 


7.26 


7.51 


7.76 


8.01 


8.26 


8.51 


8.76 


9.01 


9.26 


1.3 


1.4 


6.78 


7.03 


7.28 


7.53 


7.78 


8.03 


8.28 


8.53 


8.78 


9.03 


9.28 


1.4 


1.5 


6.80 


7.05 


7.30 


7.55 


7.80 


8.05 


8.30 


8.55 


8.80 


9.05 


9.30 


1.5 


1.6 


6.82 


7.07 


7.32 


7.57 


7.82 


8.07 


8.32 


8.57 


8.82 


9.07 


9.32 


l.C 


1.7 


6.84 


7.09 


7.34 


7.59 


7.84 


8.09 


8.34 


8.59 


8.84 


9.09 


9.34 


1.7 


l.S 


6.86 


7.11 


7.36 


7.61 


7.86 


8.11 


8.36 


8.61 


8.S6 


9.11 


9.37 


1.8 


1.9 


6.88 


7.13 


7.38 


7.63 


7.88 


8.13 


8.38 


8.63 


8.88 


9.13 


9.39 


1.9 


2.0 


6.90 


7.15 


7.40 


7.65 


7.90 


8.15 


8.40 


8.66 


8.91 


9.16 


9.41 


2.0 


2.1 


6.92 


7.17 


7.42 


7.67 


7.92 


8.17 


8.42 


8.68 


8.98 


9.18 


9.43 


2.1 


2.2 


6.94 


7.19 


7.44 


7.69 


7.94 


8.19 


8.44 


8.70 


8.95 


9.20 


9.45 


2.2 


2.3 


6.96 


7.21 


7.46 


7.71 


7.96 


8.21 


8.46 


8.72 


8.97 


9.22 


9.47 


2.3 


2.4 


6.98 


7.23 


7.48 


7.73 


7.98 


8.23 


8.48 


8.74 


8.99 


9.24 


9.49 


2.4 


2.5 


7.00 


7.25 


7.50 


7.75 


8.00 


8.25 


8.50 


8.76 


9.01 


9.26 


9.51 


2.5 


2.6 


7.02 


7.27 


7.52 


7.77 


8.02 


8.27 


8.52 


8.78 


9.03 


9.28 


9.53 


2.6 


2.7 


7... 04 


7.29 


7.54 


7.79 


8.04 


8.29 


8.54 


8.80 


9.05 


9.30 


9.55 


2.7 


2.8 


7.06 


7.31 


7.56 


7.81 


8.06 


8.31 


8.57 


8.82 


9.07 


9.32 


9.57 


2.8 


2.9 


7.08 


7.33 


7.58 


7.83 


8.08 


8.33 


8.59 


8.84 


9.09 


9.34 


9.59 


2.9 



Appendix. 239 

Table VI. Per cent, of solids not fat (Continued). 



£5^ 


Lactometer Readings at 60° F. 


*3 




26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 


3.0 


7.10 


7.35 


7.60 


7.85 


8.10 


8.36 


8.61 


8.86 


9.11 


9.36 


9.61 


3.0 


3.1 


7.12 


7.37 


7.62 


7.87 


8.13 


8.38 


8.63 


8.88 


9.13 


9.38 


9.64 


3.1 


3.2 


7.14 


7.3! 


7.64 


7.89 


S.15 


8.40 


8.65 


8.90 


9.15 


9.41 


9.66 


3.2 


3.3 


7.16 


7.41 


7.6b 


7.92 


8.17 


8.42 


8.67 


8.92 


9.18 


9.43 


9.68 


3.3 


3.4 


7.18 


7.43 


7.69 


7.94 


8.19 


8.44 


8.69 


8.94 


9.20 


9.45 


9,70 


3.4 


3.5 


7.20 


7.45 


7.71 


7.96 


8.21 


8.46 


8.71 


8.96 


9.22 


9.47 


9.72 


3.5 


3.6 


7.22 


7.48 


7.73 


7.98 


8.23 


8.48 


8.73 


8.98 


9.24 


9.49 


9.74 


3.6 


3.7 


7.24 


7.50 


7.75 


8.00 


8.25 


8.50 


8.75 


9.00 


9.26 


9.51 


9.76 


3.7 


3.8 


7.26 


7.52 


7.77 


8.02 


8.27 


8.52 


8.77 


9.02 


9.28i9.53 


9.78 


3.8 


3.9 


7.28 


7.54 


7.79 


8.04 


8.29 


8.54 


8.79 


9.04 


9.30 


9.55 


9.80 


3.9 


4.0 


7.30 


7.56 


7.81 


8.06 


8.31 


8.56 


8.81 


9.06 


9.32 


9.57 


9.83 


4.0 


4.1 


7.32 


7.58 


7.83 


8.08 


8 . 3H 


8.58 


8.83 


9.08 


9.34 


9.59 


9.85 


4.1 


4.2 


7.34 


7.60 


7.85 


8.10 


8.35 


8.60 


8.85 


9.11 


9.36 


9.62 


9.87 


4.2 


4.3 


7.36 


7.62 


7.87 


8.12 


8.37 


8.62 


8.88 


9.13 


9.38 


9.64 


9.89 


4.3 


4.4 


7.38 


7.64 


7.89 


8.14 


8.39 


8.64 


8.90 


9.15 


9.40 


9.66 


9.91 


4.4 


1.5 


7.40 


7.66 


7.91 


8.16 


8.41 


8.66 


8.92 


9.17 


9.42 


9.08 


9.93 


4.5 


4.6 


7.43 


7.68 


7.93 


8.18 


8.43 


8.68 


8.94 


9.19 


9.44 


9.70 


9.95 


4.6 


4.7 


7.45 


7.70 


7.95 


8.20 


8.45 


8.70 


8.96 


9.21 


9.46 


9.72 


9.97 


4.7 


4.8 


7.47 


7.72 


7.97 


8.22 


8.47 


8.72 


8.98 


9.23 


9.48 


9.74 


9.99 


4.8 


4.9 


7.49 


7.74 


7.99 


8.24 


8.49 


8.74 


9.00 


9.25 


9.50 


9.76 


10.01 


4.9 


5.0 


7.51 


7.76 


8.01 


8.26 


8.51 


8.76 


9.02 


9.27 


9.52 


9.78 


10.03 


5.0 


5.1 


7.53 


7.78 


8.03 


8.28 


8.53 


8.79 


9.04 


9.29 


9.54 


9.80 


10.05 


5.1 


5.2 


7.55 


7.80 


8.05 


8. SO 


8.55 


8.81 


9.06 


9.31 


9.56 


9.82 


10.07 


5.2 


5.3 


7.57 


7.82 


8.07 


8.32 


8.57 


8.83 


9.08 


9.33 


9.58 


9.84 


10.09 


5.3 


5.4 


7.59 


7.84 


8.09 


8.34 


8.60 


8.85 


9.10 


9.36 


9.61 


9.86 


10.11 


5.4 


5.5 


7.01 


7.86 


8.11 


8.36 


8.62 


8.87 


9.12 


9.38 


9.63 


9.88 


10.13 


5.5 


5.6 


7.63 


7.88 


3.13 


8.39 


8.64 


S.89 


9.15 


9.40 


9.65 


9.90 


10.15 


5.6 


5.7 


7.65 


7.90 


8.15 


8.41 


8.60 


8.91 


9.17 


9.42 


9.67 


9.92 


10.17 


5.7 


5.8 


7.67 


7.92 


8.17 


8.43 


8.68 


8.94 


9.19 


9.44 


9.69 


9.94 


10.19 


5.8 


5.9 


7.69 


7.94 


3.20 


8.45 


8.70 


8.96 


9.21 


9.46 


9.71 


9.96 


10.22 


5.9 


6.0 


7.71 


7.96 


8.22 


8.47 


8.72 


8.98 


3.28 


9.48 


3.73 


9.98 


10.2 


6^0 



240 Testing Milk and Its Products. 

Directions for Use of Tables VII, VIII, IX, and XI. 
TABLES Vil, and VIII. Find the test of the milk in table VII or 
of cream in table VIII; the first or last horizontal row of fig- 
ures, the amounts of fat in ten thousand, thousands, hundreds, 
tens, and units of pounds of milk are then given in this verti- 
cal column. By adding the corresponding figures for any given 
quantity of milk or of cream, the total quantity of butter fat 
contained therein is obtained. 

Example: How many pounds of fat is contained in 8925 lbs. of milk 
testing 3.65 per cent.? On p. 242, second column the lesL 3.63 is louud, and 
by going downward in this column we have : 

8000 lbs 292. lbs. 

900 lbs 32.9 lbs. 

20 lbs :... .7 lbs. 

5 lbs 2 lbs. 

81125 lbs. of milk. 325.8 lbs. of fat. 

8925 lbs. of milk testing 3.65 per cent., therefore, contains 325.8 lbs. of 
butter fat. 

TABLE IX. The price per pound is given in the outside vertical 

columns, and the weight of butter fat in the upper and lower 

horizontal row of figures. The corresponding tens of pounds 

are found by moving the decimal point one place to the left, 

the units, by moving it two, and the tenths of a pound, by 

moving it three places to the left. The use of the table is, 

otherwise, as explained above. 

Example: How much money is due for 325.8 lbs. of butter fat at 153^ 
cents per pound? In the horizontal row of figures beginning with 15>^ on 
p. 247, we find: 

300 lbs $46.50 

20 lbs 3.10 

5 lbs 77 

.8 lbs.. 12 

325.8 lbs. $50.49 

826.8 lbs. of butter fat at 153^ cents per pound, therefore, Is worth $50.49. 

TABLE XI. Find the test of milk in the upper or lower hori- 
zontal row of figures. The amounts of butter likely to be made 
from ten thousand, thousands, hundreds, tens,' and units of 
pounds of milk are then given in this vertical column. The use 
of the table is, otherwise, as explained above in case of table VII. 

Example: How much butter will 5845 lbs. of milk testing 3. 8 per cent, 
be apt to make under good creamery coaditions ? In the column headed 
3.8, we find : 

5000 lbs...-. 209.0 lbs. 

800 lbs 33.4 lbs. 

40 lbs 1.7 lbs. 

5 lbs 2 lbs. 

5845 lbs. 244.3 lbs. 

5845 lbs. of milk testing 3,8 per cent, of fat will make about 244.3 lbs. of 
butter, under condiLiuas similar to those explained on pp. 184-188. 



Appendix. 



241 



Table Vil. Pounds of fat in I to 10,000 lbs. of milk, testing 3.0 
to 5.35 per cent. (See directions for use, p. 240.) 



1 


3.00 


3.05 


3.10 


3.15 


3.20 


3.25 


3.3C 


3.3c 


3.4C 


3.4£ 


3.5C 


)3.55 


1 


Milk 














Milk 


lbs., 


























lbs. 


10,000 


300 


305 


310 


315 


320 


325 


330 


335 


340 


345 


350 


355 


10,000 


9,000 


270 


275 


279 


284 


289 


293 


297 


302 


306 


311 


315 


320 


9,000 


8,000 


240 


244 


248 


252 


256 


260 


264 


268 


272 


276 


280 


284 


8,000 


7,000 


210 


214 


217 


221 


224 


228 


231 


235 


238 


242 


245 


249 


7,000 


6,000 


180 


183 


186 


189 


192 


195 


198 


201 


204 


207 


210 


213 


6,000 


5,000 


150 


153 


155 


158 


160 


163 


165 


168 


170 


173 


175 


178 


5,000 


4,000 


120 


122 


124 


126 


128 


130 


132 


134 


136 


138 


140 


142 


4,000 


3,000 


90.0 


91.5 


93.0 


94.5 


96.0 


97.5 


99.0 


101 


102 


104 


105 


107 


3,000 


2,000 


60.0 


61.0 


62.0 


63.0 


64.0 


65.0 


66.0 


67.0 


68.0 


69. 


70.0 


71.0 


2,000 


1,000 


30.0 


30.5 


31.0 


31.5 


32.0 


32.5 


33.0 


33.5 


34.0 


34.5 


35.0 


35.5 


1,000 


900 


27.0 


27.5 


27.9 


28.4 


28.8 


29.3 


29.7 


30.2 


30.6 


31.1 


31.5 


32.0 


900 


800 


24.0 


24.4 


24.8 


25.2 


25.7 


26.0 


26.4 


26.8 


27.2 


27.6 


28.0 


28.4 


800 


700 


21.0 


21.4 


21.7 


22.1 


22.4 


22.8 


23.1 


23.5 


23.8 


24.2 


24.5 


24.9 


700 


600 


18.0 


18.3 


18.6 


18.9 


19.2 


19.5 


19.8 


20.1 


20.4 


20.7 


21.0 


21.3 


600 


500 


15.0 


15.3 


15.5 


15.8 


16.0 


16.3 


16.5 


16.8 


17.0 


17.3 


17.5 


17.8 


500 


400 


12.0 


12.2 


12.4 


12.6 


12.8 


13.0 


13.2 


13.4 


13.6 


13.8 


14.0 


14.2 


400 


300 


9.0 


9.2 


9.3 


9.5 


9.6 


9.8 


9.9 


10.1 


10.2 


10.4 


10.5 


10.7 


300 


200 


6.0 


6.1 


6.2 


6.3 


6.4 


6.5 


6.6 


6.7 


6.8 


6.9 


7.0 


7.1 


200 


100 


3.0 


3.1 


3.1 


3.2 


3.2 


3.3 


3.3 


3.4 


3.4 


3.5 


3.5 


3.6 


100 


90 


2.7 


2.8 


2.8 


2.8 


2.9 


2.9 


3.0 


3.0 


3.1 


3.1 


3.2 


3.2 


90 


80 


2.4 


2.4 


2.5 


2.5 


2.6 


2.6 


2.6 


2.7 


2.7 


2.8 


2.8 


2.8 


80 


70 


2.] 


2.1 


2.2 


2.2 


2.2 


2.3 


2.3 


2.3 


2.4 


2.4 


2.5 


2.5 


70 


60 


1.8 


1.8 


1.9 


1.9 


1.9 


2.0 


2.0 


2.0 


2.0 


2.1 


2.1 


2.1 


60 


50 


1.5 


1.5 


1.6 


1.6 


1.6 


1.6 


1.7 


1.7 


1.7 


1.7 


1.8 


1.8 


50 


40 


1.2 


1.2 


1.2 


1.3 


1.3 


1.3 


1.3 


1.3 


1.4 


1.4 


1.4 


1.4 


40 


30 


.9 


.9 


.9 


.9 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.1 


1.1 


30 


20 


.6 


.6 


.6 


.6 


.6 


.7 


.7 


.7 


.7 


.7 


.7 


.7 


20 


10 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


10 


9 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


9 


8 


.2 


,2 


.2 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


8 


7 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


7 


6 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


t2 


.2 


.2 


.2 


6 


5 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


4 


3 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 

1 


.1 


.1 


.1 


.1 


.1 


1 


.1 


.1 


.1 


.1 


.1 


.1 


2 
1 


1 


3.00 


3.05 


3.10 


3.15 


3.20 


3.25 


3.30 


3.35 


3.40 


3.45 { 


3.50 


3.55 


r 



le 



242 Testing Milk and Its Products. 

Table Yd. Pounds of fat in I to 10,000 lbs. of milk ( Continued), 



CO 


3.60 


3.65 


3.70 


3.75 


3.80 


3.85 


3.90 


3.95 


4.00 


4.05 


4.10 


4.15 


^ 
^ 


Milk 


























Milk 


lbs. 


























lbs. 


10,000 


360 


365 


370 


375 


380 


385 


390 


395 


400 


405 


410 


415 


10,000 


9,000 


324 


329 


333 


338 


342 


347 


351 


856 


360 


365 


369 


374 


9,000 


8,000 


288 


292 


296 


300 


304 


308 


312 


316 


320 


324 


328 


332 


8,000 


7.000 


252 


256 


259 


268 


266 


270 


273 


277 


280 


284 


287 


291 


7,000 


6,000 


216 


219 


222 


225 


228 


231 


284 


237 


240 


243 


246 


249 


6,000 


5,000 


180 


183 


185 


188 


190 


193 


195 


198 


200 


203 


205 


208 


5,000 


4,000 


144 


146 


148 


150 


152 


154 


156 


158 


160 


162 


164 


166 


4,000 


3,000 


108 


110 


111 


113 


114 


116 


117 


119 


120 


122 


123 


125 


3,000 


2,000 


72.0 


73.0 


74.0 


75.0 


76.0 


77.0 


78.0 


79.0 


80.0 


81.0 


82.0 


83.0 


2,000 


1,000 


36.0 


36.5 


37.0 


37.5 


38.0 


38.5 


39.0 


39.5 


40.0 


40.5 


41.0 


41.5 


1,000 


900 


32.4 


32.9 


33.3 


83.8 


84.2 


84.7 


35.1 


35.6 


86.0 


36.5 


36.9 


37.4 


900 


800 


28.8 


29.2 


29.6 


30.0 


30.4 


80.8 


31.2 


81.6 


82.0 


32.4 


82.8 


33.2 


800 


700 


25.2 


25.6 


25.9 


26.8 


26.6 


27.0 


27.3 


27.7 


28.0 


28.4 


28.7 


29.1 


700 


600 


21.6 


21.9 


22.2 


22.5 


22.8 


28.1 


28.4 


28.7 


24.0 


24.8 


24.6 


24.9 


600 


500 


18.0 


18.3 


18.5 


18.8 


19.0 


19.8 


19.5 


19.8 


20.0 


20.3 


20.5 


20.8 


500 


400 


14.4 


14.6 


14.8 


15.0 


15.2 


15.4 


15.6 


15.8 


16.0 


16.2 


16.4 


16.6 


400 


300 


10.8 


11.0 


11.1 


11.3 


11.4 


11.6 


11.7 


11.9 


12.0 


12.2 


12.3 


12.5 


300 


200 


7.2 


7.3 


7.4 


7.5 


7.6 


7.7 


7.8 


7.9 


8.0 


8.1 


8.2 


8.3 


200 


100 


3.6 


3.7 


3.7 


3.8 


3.8 


3.9 


3.9 


4.0 


4.0 


4.1 


4.1 


4.2 


100 


90 


3.2 


3.3 


3.3 


3.4 


8.4 


8.5 


8.5 


8.6 


3.6 


3.7 


3.7 


3.7 


90 


80 


2.9 


2.9 


3.0 


3.0 


8.0 


3.1 


3.1 


3.2 


8.2 


3.2 


3.3 


3.3 


80 


70 


2.5 


2.6 


2.6 


2.6 


2.7 


2.7 


2.7 


2.8 


2.8 


2.8 


2.9 


2.9 


70 


. 60 


2.2 


2.2 


2.2 


2.3 


2.8 


2.3 


2.8 


2.4 


2.4 


2.4 


2.5 


2.5 


60 


50 


1.8 


1.8 


1.9 


.1.9 


1.9 


1.9 


2.0 


2.0 


2.0 


2.0 


2.1 


2.1 


50 


40 


1.4 


1.5 


1.5 


1.5 


1.5 


1.5 


1.6 


1.6 


1.6 


1.6 


1.6 


1.7 


40 


80 


1.1 


1.1 


1.1 


1.1 


1.1 


1.2 


1.2 


1.2 


1 2 


1.2 


1.2 


1.2 


30 


20 


.7 


.7 


.7 


.8 


.8 


.8 


.8 


.8 


.8 


.8 


.8 


.8 


20 


10 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


10 


9 


.3 


.3 


.3 


.3 


.8 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


9 


8 


.3 


.3 


.3 


.3 


.3 


.8 


.3 


.3 


.3 


.3 


.3 


.3 


8 


7 


.3 


.3 


.3 


.3 


.8 


.8 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


6 


5 


.2 


.2 


.2 


.2 


.2 


.1. 


.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


.1 


.1 


.1 


.2 


.2 


2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


8 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 

1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


2 

1 


1 


3.60 


3.65 


3.70 


3.75 


3.80 


3.85 


3.90 


3.95 


4.00 


4.05 


4.10 


4.15 


I 



Appendix. 



243 



Table VII. Pounds of fat w 


1 1 to 10,000 lbs. of milk 


{Continued). 


Test. 


4.20 


4.25 


4.30 


4.35 


4.40 


4.45 


4.50 


4.55 


4.60 


4.65 


4.70 


4.75 


^ 


Milk 














Milk 


lbs. 


























lbs. 


10,000 


420 


425 


430 


435 


440 


445 


450 


455 


4^0 


465 


470 


475 


10,000 


9,000 


378 


383 


387 


392 


396 


401 


405 


410 


414 


419 


423 


428 


^,000 


8,000 


336 


340 


344 


348 


352 


356 


360 


364 


368 


372 


376 


380 


8,000 


7,000 


294 


298 


301 


305 


308 


312 


315 


319 


322 


326 


329 


333 


7,000 


6,000 


252 


255 


258 


261 


264 


267 


270 


273 


276 


279 


282 


285 


6,000 


5,000 


210 


213 


215 


218 


220 


223 


225 


228 


230 


233 


235 


238 


5,0(0 


4,000 


168 


170 


172 


174 


176 


178 


180 


182 


184 


186 


188 


190 


4,000 


3,030 


126 


128 


129 


131 


132 


134 


135 


137 


138 


140 


141 


143 


3,000 


2,000 


84.0 


85.0 


86.0 


87.0 


88.0 


89.0 


90.0 


91.0 


92.0 


93.0 


94.0 


95.0 


2,000 


1,000 


42.0 


42.5 


43.0 


43.5 


44.0 


44.5 


45.0 


45.5 


46.0 


46.5 


47.0 


47.5 


1,000 


900 


37.8 


3S.3 


38.7 


39.2 


39.6 


40.1 


40.5 


41.0 


41.4 


41.9 


42.3 


42.8 


900 


800 


33.6 


3k0 


34.4 


34.8 


35.2 


35.6 


36.0 


36.4 


36.8 


37.2 


37.6 


38.0 


800 


700 


29.4 


29.8 


80.1 


30.5 


30.8 


31.2 


31.6 


31.9 


32.2 


32.6 


32.9 


33.3 


700 


600 


25.2 


25.5 


5.8 


26.1 


26.4 


26.7 


27.0 


27.3 


27.6 


27.9 


28.2 


28.5 


600 


500 


21.0 


21.3 


21.5 


21.8 


22.0 


22.3 


22.5 


22.8 


23.0 


23.3 


23.5 


23.8 


500 


400 


16.8 


17.0 


17.2 


17.4 


17.6 


17.8 


18.0 


18.2 


18.4 


18.6 


18.8 


19.0 


400 


300 


12.6 


12.8 


12.9 


13.1 


13.2 


13.4 


13.5 


13.7 


13.8 


14.0 


14.1 


14.3 


300 


200 


8.4 


8.5 


8.0 


8.7 


8.8 


8.9 


9.0 


9.1 


9.2 


9.3 


9.4 


9.5 


200 


100 


4.2 


4.3 


4.3 


4.4 


4.4 


4.5 


.4.5 


4.6 


4.6 


4.7 


4.7 


4.8 


100 


90 


.3.8 


3.8 


3.9 


3.9 


4.0 


4.0 


4.1 


4.1 


4.1 


4.2 


4.2 


4.3 


90 


80 


3.4 


3.4 


3.4 


3.5 


3.5 


3.6 


3.6 


3.6 


3.7 


3.7 


3.8 


3.8 


80 


70 


2.9 


3.0 


3.0 


3.0 


3.1 


3.1 


3.2 


3.2 


3.2 


3.3 


3.3 


3.8 


70 


60 


2.5 


2.6 


2.6 


2.6 


2.6 


2.7 


2.7 


2.7 


2.8 


2.8 


2.8 


2 9 


60 


50 


2.1 


2.1 


2.2 


2.2 


2.2 


2.2 


2.3 


2.3 


2.3 


2.3 


2.4 


2.4 


50 


40 


1.7 


1.7 


1.7 


1.7 


1.8 


1.8 


1.8 


1.8 


1.8 


1.9 


1.9 


1.9 


40 


30 


1.3 


1.3 


1.3 


1.3 


1.3 


1.3 


1.4 


1.4 


1.4 


1.4 


1.4 


1.4 


30 


20 


.8 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


1.0 


20 


10 


.4 


.4 


.4 


.4 


.4 


.4 


.5 


.5 


.5 


.5 


.5 


.5 


10 


9 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


9 


8 


.3 


.3 


.3 


.3 


.4 


.4 


.4 


.4 


.4 


4 


.4 


.4 


8 


7 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


.3 


.3 


.3 


.3 


.8 


.3 


£, 


.3 


.3 


.3 


.3 


.3 


6 


5 


.2 


.2 


.2 


.2 


.2 


.2 


'.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


.2 


.2 


.2 


.2 


.2 


.2 


2 


.2 


.2 


.2 


.2 


.2 


4 


3 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 
1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


• 2 




4.20 


4.25 


4.30 


4.35 


4.40 


4.45 


4.50 


4.55 


4.60 


4.65 


4.70 


4.75 




^ 

^ 


7* 



244 Testing Milk and Its Products. 

Table VII. Pounds of fat in I to 10,000 lbs. of milk ( Continued). 



^ 

1 


4.80 


4.85 


4.90 


4.95 


5.00 


5.05 


5.10 


5.15 


5.20 


5.25 


5.30 


5.35 




Milk 














Milk 


lbs. 


























lbs. 


10,000 


480 


485 


490 


495 


500 


505 


510 


515 


520 


525 


530 


535 


10,000 


9,000 


432 


437 


441 


446 


450 


455 


459 


464 


468 


473 


477 


482 


9,000 


8,000 


384 


388 


392 


396 


400 


404 


408 


412 


416 


420 


424 


428 


8,000 


7,000 


336 


340 


343 


347 


350 


354 


357 


361 


364 


368 


371 


375 


7,000 


6,000 


288 


291 


294 


297 


300 


303 


306 


309 


312 


315 


318 


321 


6,000 


5,000 


240 


243 


245 


248 


250 


253 


255 


258 


260 


263 


265 


268 


5,000 


4,000 


192 


194 


196 


198 


200 


202 


204 


206 


208 


210 


212 


214 


4,000 


8,000 


144 


146 


147 


149 


150 


152 


153 


155 


156 


158 


159 


161 


3,000 


2,000 


96.0 


97.0 


98.0 


99.0 


100 


101 


102 


103 


104 


105 


106 


107 


2,000 


1,000 


48.0 


48.5 


49.0 


49.5 


50.0 


50.5 


51.0 


51.5 


52.0 


52.5 


53.0 


53.5 


1,000 


900 


43.2 


43.7 


44.1 


44.6 


45.0 


45.5 


45.7 


46.4 


46.8 


47.3 


47.7 


48.2 


900 


800 


38.4 


38.8 


39.2 


39.6 


40.0 


40.4 


40.8 


41.2 


41.6 


42.0 


42.4 


42.8 


800 


700 


33.6 


34.0 


34.3 


34.7 


35.0 


35.4 


35.7 


36.1 


36.4 


36.8 


37.1 


37.5 


700 


600 


28.8 


29.1 


29.4 


29.7 


30.0 


30.3 


30.6 


30.9 


31.2 


31.5 


31.8 


32.1 


600 


500 


24.0 


24.3 


24.5 


24.8 


25.0 


25.3 


25.5 


25.8 


26.0 


26.3 


26.5 


26.8 


500 


400 


19.2 


19.4 


19.6 


19.8 


20.0 


20.2 


20.4 


20.6 


20.8 


21.0 


21.2 


21.4 


400 


300 


14.4 


14.6 


14.7 


14.9 


15.0 


15.2 


15.3 


15.5 


15.6 


15.8 


15.9 


16.1 


300 


200 


9.6 


9.7 


9.8 


9.9 


10.0 


10.1 


10.2 


10.3 


10.4 


10.5 


10.6 


10.7 


200 


100 


4.8 


4.9 


4.9 


5.0 


5.0 


5.1 


5.1 


5.2 


5.2 


5.3 


5.3 


5.4 


100 


90 


4.3 


4.4 


4.4 


4.5 


4.5 


4.5 


4.6 


4.6 


4.7 


4.7 


4.8 


4.8 


90 


80 


3.8 


3.9 


3.9 


4.0 


4.0 


4.0 


4.1 


4.1 


4.2 


4.2 


4.2 


4.3 


80 


70 


3.4 


3.4 


3.4 


3.5 


3.5 


3.5 


3.6 


3.6 


3.6 


3.7 


3.7 


3.7 


70 


60 


2.9 


2.9 


2.9 


3.0 


3.0 


3.0 


3.1 


3.1 


3.1 


3.2 


3.2 


3.2 


60 


50 


2.4 


2.4 


2.5 


2.5 


2.5 


2.5 


2.6 


2.6 


2.6 


2.6 


2.7 


2.7 


50 


40 


1.9 


1.9 


2.0 


2.0 


2.0 


2.0 


2.0 


2.1 


2.1 


2.1 


2.1 


2.1 


40 


30 


1.4 


1.5 


1.5 


1.5 


1.5 


1.5 


1.5 


1.5 


1.6 


1.6 


1.6 


1.6 


30 


20 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.1 


1.1 


1.1 


20 


10 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


' .5 


.5 


• .5 


.5 


10 


9 


.4 


.4 


.4 


.4 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


9 


8 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


8 


7 


.3 


.3 


.3 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


7 


(•) 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 





5 


.2 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


.3 


■ .3 


.3 


.3 


5 


4 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


3 


.1 


.1 


.1 


.1 


.2 


.2 


.2 


.2 


.2 


9 


.2 


.2 


3 


o 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


2 


1 










.1 

5.00 


.1 

5.05 


.1 

5.10 


.1 
5.15 


.1 
5.20 


.1 

5.25 


.1 

5.30 


.1 

5.35 


1 




4.80 


4.85 


4.90 


4.95 




^ 

'& 


1 



Appendia}. 



245 



Table VIII. Pounds of fat in I to 1000 lbs. of cream testing 
12.0 to 50.0 per cent. fat. 

(See directions for use, p. 240.) 





12 


13 


14 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


25 


26 


27 


28 


29 


30 


1000 


120 


180 


140 


150 


160 


170 


180 


190 


200 


210 


220 


230 


240 


250 


260 


270 


280 


290 


300 


yoo 


108 


117 


126 


185 


144 


153 


162 


171 


180 


1811 


198 


207 


216 


225 


284 


243 


252 


261 


270 


800 


96 


104 


112 


120 


128 


136 


144 


152 


160 


168 


176 


184 


192 


200 


208 


216 


224 


232 


240 


700 


84 


91 


98 


105 


112 


119 


126 


133 


HO 


147 


154 


161 


168 


175 


182 


189 


196 


208 


210 


600 


72 


78 


84 


90 


96 


102 


108 


114 


120 


126 


132 


138 


144 


150 


156 


162 


168 


174 


180 


600 


60 


65 


70 


75 


80 


85 


90 


95 


100 


105 


110 


115 


120 


125 


130 


136 


140 


145 


150 


400 


48 


52 


66 


60 


64 


68 


72 


76 


80 


84 


88 


92 


96 


100 


104 


108 


112 


116 


120 


300 


36 


39 


42 


45 


48 


51 


54 


57 


60 


63 


66 


69 


72 


76 


78 


81 


84 


87 


90 


200 


24 


26 


28 


30 


32 


34 


36 


38 


40 


42 


44 


46 


48 


50 


62 


64 


6b 


58 


60 


100 


12 


13 


14 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


25 


26 


27 


28 


29 


30 


90 


10.8 


11.7 


12.6 


13.5 


14.4 


15.3 


16.2 


17.1 


18.0 


18.9 


19.8 


20.7 


21.6 


22.5 


23.4 


24.3 


25.2 


26.1 


27.0 


80 


9.6 


10.4 


11.2 


12.0 


12.8 


13.6 


14.4 


15.2 


16.0 


16.8 


17.6 


18.4 


19.2 


JO.O 


20.8 


21.6 


22.4 


23.2 


24.0 


70 


8.4 


9.1 


9.8 


10.5 


11.2 


11.9 


12.6 


13.8 


14.0 


14.7 


15.4 


16.1 


16.8 


17.5 


18.2 


18.9 


19.6 


20..3 


21.0 


60 


7.2 


7.8 


8.4 


9.0 


9.6 


10.2 


10.8 


11.4 


12.0 


12.6 


13.2 


13.8 


14.4 


15.0 


15.6 


16.2 


16.8 


17.4 


18.0 


60 


6.0 


6.5 


7.0 


7.5 


8.0 


8.5 


9.0 


9.5 


10.0 


10.5 


11.0 


11.5 


12.0 


12.5 


13.0 


13.5 


14.0 


14.5 


15.0 


40 


4.8 


5.2 


6.6 


6.0 


6.4 


6.8 


7.2 


7.6 


8.0 


8.4 


8.8 


9.2 


9.6 


10.0 


10.4 


10.8 


11.2 


11.6 


12.0 


30 


3.6 


3.9 


4.2 


4.5 


4.8 


6.1 


5.4 


5.7 


6.0 


6.3 


6.6 


6.9 


7.2 


7.5 


7.8 


8.1 


8.4 


8.7 


9.0 


20 


2.4 


2.6 


2.8 


3.0 


3.2 


3.4 


3.6 


3.8 


4.0 


4.2 


4.4 


4.6 


4.8 


6.0 


5.2 


6.4 


6.6 


5.8 


6.0 


10 


1.2 


1.3 


1.4 


1.6 


1.6 


1.7 


1.8 


1.9 


2.0 


2.1 


2.2 


2.3 


2.4 


2.5 


2.6 


2.7 


2.8 


2.9 


3.0 


9 


1.08 


1.17 


1.26 


1.35 


1.44 


1.53 


1.62 


1.71 


1.80 


1.89 


1.98 


2.07 


2.16 


2.25 


2.34 


1.43 


2.52 


2.61 


2.70 


8 


.96 


1.04 


1.12 


1.20 


1.28 


1.36 


1.44 


1.52 


1.60 


1.68 


1.76 


1.84 


1.92 


2.00 


2.08 


2.16 


2.24 


2.32 


2.40 


7 


.84 


.91 


.98 


1.05 


1.12 


1.19 


1.26 


1.33 


1.40 


1.47 


1.54 


1.61 


1.68 


1.75 


1.82 


1.89 


1.96 


2.03 


2.10 


6 


.72 


.78 


.84 


.90 


.96 


1.02 


1.08 


1.14 


1.20 


1.26 


1.32 


1.38 


1.44 


1.50 


1.56 


1.62 


1.68 


1.74 


1.80 


5 


.60 


.65 


.70 


.75 


.80 


.85 


.90 


.95 


1.00 


1.05 


1.10 


1.15 


1.20 


1.25 


1.30 


1.35 


1.40 


1.45 


1.50 


4 


.48 


.52 


.66 


.60 


.64 


.68 


.72 


.76 


.80 


.84 


.88 


.92 


.96 


1.00 


1.04 


1.08 


1.12 


1.16 


1.20 


3 


.86 


.39 


.42 


.45 


.48 


.51 


.54 


.57 


.60 


.63 


.66 


.69 


.72 


.75 


.78 


.81 


.84 


.87 


.90 


2 


.24 


.26 


.28 


.30 


.32 


.34 


.36 


.38 


.40 


.42 


.44 


.46 


.48 


.50 


.52 


.54 


.56 


.58 


.60 


1 


.12 


.13 


.14 


.16 


.16 


.17 


.18 


.19 


.20 


.21 


.22 


.23 


.24 


.25 


.26 


.27 


.28 


.29 


.30 



246 



Testing Milk and Its Products. 



Table VIII. Pounds of fat in I to 1000 lbs. of cream {continued). 



1 


31 


32 


33 


34 


35 


86 


37 


38 


39 


40 


41 


42 


43 


44 


45 


46 


47 


48 


49 


50 


1000 


310 


320 


380 


340 


350 


360 


370 


380 


390 


400 


410 


420 


430 


440 


450 


m 


470 


480 


490 


500 


900 


279 


288 


297 


306 


315 


324 


338 


342 


351 


360 


369 


378 


387 


896 


405 


414 


423 


432 


441 


450 


800 


248 


256 


264 


272 


280 


288 


2C6 


304 


812 


320 


328 


386 


344 


352 


360 


368 


376 


384 


392 


400 


700 


217 


224 


231 


238 


245 


252 


259 


266 


278 


280 


287 


294 


301 


308 


315 


322 


829 


886 


843 


850 


600 


186 


192 


198 


204 


210 


216 


222 


228 


234 


240 


246 


252 


258 


264 


270 


276 


282 


288 


294 


300 


500 


155 


160 


165 


170 


175 


180 


185 


190 


195 


200 


205 


210 


215 


220 




230 


235 


240 


245 


250 


400 


124 


128 


132 


136 


140 


144 


148 


152 


156 


160 


164 


168 


172 


176 


180 


184 


188 


192 


196 


200 


800 


93 


96 


99 


102 


105 


108 


111 


114 


117 


120 


123 


126 


129 


132 


135 


138 


141 


144 


147 


150 


200 


62 


64 


66 


68 


70 


72 


74 


76 


78 


80 


82 


84 


86 


88 


90 


92 


94 


96 


98 


100 


100 


81 


32 


83 


34 


35 


36 


87 


38 


89 


40 


41 


42 


48 


44 


45 


46 


47 


48 


.49 


60 


90 


27.9 


28.8 


29.7 


30.6 


31.5 


32.4 


33.3 


34.2 


35.1 


86.0 


36.9 


87.8 


38.7 


39.6 


40.5 


41.4 


42.3 


48.2 


44.1 


46.0 


80 


24.8 


25.6 


26.4 


27.2 


28.0 


28.8 


29.6 


80.4 


21.2 


32.0 


32.8 


33.6 


34.4 


35.2 


36.0 


36.8 


37.6 


38.4 


39.2 


40.0 


70 


21.7 


22.4 


23.1 


23.8 


24.5 


25.2 


25.9 


26.6 


27.3 


28.0 


28.7 


29.4 


30.1 


30.8 


31.5 


32.2 


32.9 


88.6 


34.3 


36.0 


60 


18.6 


19.2 


19.8 


20.4 


21.0 


21.6 


22.2 


22.8 


23.4 


24.0 


24.6 


25.2 


25.8 


26.4 


27.0 


27.6 


28.2 


28.8 


29.4 


80.0 


50 


15.5 


16.0 


16.6 


17.0 


17.5 


18.0 


18.5 


19.0 


19.5 


20.0 


20.5 


21.0 


21.5 


22.0 


22.5 


23.0 


23.5 


24.0 


24.5 


26.0 


40 


12.4 


12.8 


13.2 


13.6 


14.0 


14.4 


14.8 


15.2 


15.6 


16.0 


16.4 


16.8 


17.2 


17.6 


18.0 


18.4 


18.8 


19.2 


19.6 


20.0 


80 


9.8 


9.6 


9.9 


10.2 


10.5 


10.8 


11.1 


11.4 


11.7 


12.0 


12.8 


12.6 


12.9 


13.2 


13.5 


18.8 


14.1 


14.4 


14.7 


15.0 


20 


6.2 


6.4 


6.ff 


6.8 


7.0 


7.2 


7.4 


7.6 


7.8 


8.0 


8.2 


8.4 


8.6 


8.8 


9.0 


9.2 


9.4 


0.6 


9.8 


10.0 


10 


3.1 


3.2 


3.3 


3.4 


3.5 


3.6 


3.7 


3.8 


8.9 


4.0 


4.1 


4.2 


4.3 


4.4 


4.5 


4.6 


4.7 


4.8 


4.9 


5.0 


9 


2.79 


2.88 


2.97 


3.06 


3.15 


3.24 


3.33 


3.42 


3.51 


3.60 


3.69 


3.78 


3.87 


3.96 


4.95 


4.14 


4.23 


4.32 


4.41 


4.60 


8 


2.48 


2.56 


2.64 


2.72 


2.80 


2.88 


2.96 


3.04 


3.12 


3.20 


3.28 


3.36 


3.44 


3.52 


3.60 


8.68 


3.76,3.84 


3.92 


4.00 


7 


2.17 


2.24 


2.31 


2.38 


2.45 


2.52 


2.59 


2.66 


2.73 


2.80 


2.87 


2.94 


3.01 


3.08 


3.15 


8.22 


3.29 


8.36 


3.43 


3.60 


6 


1.86 


1.92 


1.98 


2.04 


2.10 


2.16 


2.22 


2.28 


2.34 


2.40 


2.46 


2.52 


2.58 


2,64 


2.70 


2.76 


2.82 


2.88 


2.94 


3.00 


5 


1.55 


1.60 


1.65 


1.70 


1.75 


1.80 


1.85 


1.90 


1.95 


2.00 


2.05 


2.10 


2.15 


2.20 


2.25 


2.30 


2.35 


2.40 


2.45 


2.50 


4 


1.24 


1.28 


1.32 


1.36 


1.40 


1.44 


1.48 


1.52 


1.56 


1.60 


1.64 


1.68 


1.72 


1.76 


1.80 


1.84 


1.88 


1.92 


1.96 


2.00 


3 


.93 


.96 


.99 


1.02 


l.Oo 


1.08 


1.11 


1.14 


1.17 


1.20 


1.23 


1.26 


1.29 


1.32 


1.35 


1.38 


1.41 


1.44 


1.47 


1.50 


2 


.62 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


.80 


.82 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


1.00 


1 


.31 


.32 


.33 


.34 


.35 


.86 


.37 


.88 


.89 


.40 


.41 


.42 


.43 


.44 


.45 


.46 


.47 


.48 


.49 


.50 



Appendix. 



247 



Tabto IX. Amount due for butter fat, in dollars and cents, at 
12 to 25 cents per pound. 

(See directions for use, page 240.) 



d 


Pounds of butter fat. 


h 

1" 




1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 


12 
12i 

11 

13 

13i 
13| 
13| 

14 

m 

141 

15 

15i 
15^ 
151 

16 
16i 
16^ 
16| 

17 

m 

171 

18 

18^^ 
18^ 
18| 


$ 

120.00 
122.50 
125.00 
127.50 

130.00 
132.50 
135.00 
137.50 

140.00 
142.50 
145.00 
147.50 

150.00 
152.50 
1^5.00 
157.50 

160.00 
162.50 
165.00 
167.50 

170.00 
172.50 
175.00 
177.50 

180.00 
182.50 
185.00 
187.50 


$ 

108.00 
110.25 
112.50 
114.75 

117.00 
119.25 
121.50 
123.75 

126.00 
128.25 
130.50 
132.75 

135.00 
137.25 
139.50 
141.75 

144.00 
146.25 
148.50 
150.75 

153.00 
155.25 
157.50 
159.75 

162.00 
164.25 
166.50 
168.75 


$ 

96.00 

98.00 

100.00 

102.00 

104.00 
106.00 
108.00 
110.00 

112.00 
114.00 
116.00 
118.00 

120.00 
122.00 
124.00 
126.00 

128.00 
130.00 
132.00 
134.00 

136.00 
138.00 
140.00 
142.00 

144.00 
146.00 
148.00 
150.00 


$ 

84.00 
85.75 
87.50 
89.25 

91.00 
92.75 
94.50 
96.25 

98.00 

99.75 

101.50 

103.25 

105.00 
106.75 
108.50 
110.25 

112.00 
113.75 
115.50 
117.25 

119.00 
120.75 
122.50 
124.25 

126.00 
127.75 
129.50 
131.25 


$ 

72.00 
73.50 
75.00 
76.50 

78.00 
79.50 
81.00 
82.50 

84.00 
85.50 
87.00 
88.50 

90.00 
91.50 
93.00 
94.50 

96.00 

97.50 

99.00 

100.50 

102.00 
103.50 
105.00 
106.50 

108.00 
109.50 
111.00 
112.50 


60.00 
61.25 
62.50 
63.75 

65.00 
66.25 
67.50 
68.75 

70.00 
71.25 
72.50 
73.75 

75.00 
76.25 
77.50 

78.75 

80.00 
81.25 
82.50 
83.75 

85.00 
86.25 
87.50 

87.75 

90.00 
91.25 
92.50 
93.75 


$ 

48.00 
49.00 
50.00 
51.00 

52.00 
53.00 
54.00 
55.00 

56.00 
57.00 
58.00 
59.00 

60.00 
61.00 
62.00 
63.00 

64.00 
65.00 
66.00 
67.00 

68.00 
69.00 
70.00 
71.00 

72.00 
73.00 
74.00 
75.00 


$ 

36.00 
36.75 
37.50 

38.25 

39.00 
39.75 
40.50 
41.25 

42.00 
42.75 
43.50 
44.25 

45.00 
45.75 
46.50 
47.25 

48.00 
48.75 
49.50 
50.25 

51.00 
51.75 
52.50 
53.25 

54.00 
54.75 
55.50 
56.25 


$ 

24.00 
24.50 
25.00 
25.50 

26.00 
26.50 
27.00 
27.50 

28.00 
28.50 
29.00 
29.50 

30.00 
30.50 
31.00 
31.50 

32.00 
32.50 
33.00 
33.50 

34.00 
34.50 
35.00 
35.50 

36.00 
36.50 
37.00 
37.50 


$ 

12.00 
12.25 
12.50 
12.75 

13.00 
13.25 
13.50 
13.75 

14.00 
14.25 
14.50 
14.75 

15.00 
15.25 
15.50 
15.75 

16.00 
16.25 
16.50 
16.75 

17.00 
17.25 
17.50 
17.75 

18.00 
18.25 
18.50 
18.75 


12 
12i 

13 
13i 

111 

14 

14J 
14^ 
14| 

15 
15^ 
15i 
15f 

16 

16^ 

17 
17J 

17f 

18 

18i 
18^ 
181 




1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 


• 



248 Testing Milk and Its Products. 

lable IX. Aniount due for butter fat {Continued), 





Pounds of butter f^t. 


1. 

1^ 


■1% 


1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 


19 

19i 

19* 

191 

20 
20i 

21 

21i 
21J 
21f 

22 

22i 
22^ 
221 

23 

23i 

23J 
23| 

24 

24} 
24^ 
24| 
25 


$ 

190.00 
192.50 
195.00 
197.50 

200.00 
202.50 
205.00 
207.50 

210.00 
212.50 
215.00 
217.50 

220.00 
222.50 
225.00 
227.50 

230.00 
232.50 
235.00 
237.50 

240.00 
242.50 
245.00 
247.50 
250.00 


$ 

171.00 
173.25 
175.50 
177.75 

180.00 
182.25 
184.50 
186.75 

189.00 
191.25 
193.50 
195.75 

198.00 
200.25 
202.50 
204.75 

207.00 
209.25 
211.50 
213.75 

216.00 

218.25 
220.50 
222.75 
225.00 


$ 

152.00 
154.00 
156.00 
158.00 

160.00 
162.00 
164.00 
166.00 

168.00 
170.00 
172.00 
174.00 

176.00 

178.00 
180.00 
182.00 

184.00 
186.00 
188.00 
190.00 

192.00 
194.00 
196.00 
198.00 
200.00 


% 

133.00 
134.75 
130.50 
138.25 

140.00 
141.75 
143.50 
145.25 

147.00 
148.75 
150.50 
152.25 

154.00 
155.75 
157.50 
159.25 

161.00 
162.75 
164.50 
166.25 

168.00 
169.75 
171.50 
173.25 
175.00 


$ 

114.00 
115.50 
117.00 
118.50 

120.00 
121.50 
123.00 
124.50 

126.00 
127.50 
129.00 
130.50 

132.00 
133.50 
135.00 
136.50 

138.00 
139.50 
141.00 
142.50 

144.00 
145.50 
147.00 
148.50 
150.00 


95.00 
96.25 
97.50 

98.75 

100.00 
101.25 
102.50 
103.75 

105.00 
106.25 
107.50 

108.75 

110.00 
111.25 
112.50 
113.75 

115.00 
116.25 
117.50 
118.75 

120.00 
121.25 
122.50 
123.75 
125.00 


$ 

76.00 
77.00 
78.00 
79.00 

80.00 
81.00 
82.00 
83.00 

84.00 
85.00 
86.00 
87.00 

88.00 
89.00 
90.00 
91.00 

92.00 
93.00 
94.00 
95.00 

96.00 
97.00 
98.00 
99.00 
100.00 


$ 
57.00 
57.75 
58.50 
59.25 

60.00 
60.75 
61.50 
62.25 

63.00 
63.75 
64.50 
65.25 

66.00 
66.75 
67.50 

68.25 

69.00 
69.75 
70.50 
71.25 

72.00 
72.75 
73.;»0 
74.25 
75.00 


$ 

38.00 
38.50 
39.00 
39.50 

40.00 
40.50 
41.00 
41.50 

42.00 
42.50 
43.00 
43.50 

44.00 
44.50 
45.00 
45.50 

46.00 
46.50 
47.00 
47.50 

48.00 
48.50 
49.00 
49.50 
50.00 


19.00 
19.25 
19.50 
19.75 

20.00 
20.25 
20.50 
20.75 

21.00 
21.25 
21.50 
21.75 

22.00 
22.25 
22.50 
22.75 

23.00 
23.25 
23.50 
23.75 

24.00 
24.25 
24.. 50 
24.75 
25.00 


19 

19} 
19| 
19| 

20 
20} 
2O2 
201 

21 

21} 
21i 
21f 

22- 

221 

23 

23} 

23^ 

24 

m 

241 
25 




1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 





Appendix, 



249 



Table X. Relative-value tab!es. 

(See directions for use, pp. 196-198. 



*2 


Price of milk per 100 pounds, in dollars and cents. 


3.0 


.30 


.31 


.83 


.34 


.36 


.37 


.39 


.40 


.42 


.43 


.46 


3.1 


.31 


.33 


.34 


.36 


.37 


.39 


.40 


.42 


.43 


.45 


.46 


3.2 


.32 


.34 


.35 


.37 


.38 


.40 


.42 


.43 


.46 


.46 


.48 


3.3 


.33 


.35 


.36 


.38 


.40 


.41 


.43 


.45 


.46 


.48 


.49 


3.4 


.34 


.36 


.37 


.39 


.41 


.42 


.44 


.46 


.48 


.49 


.51 


3.5 


.35 


.37 


.38 


.40 


.42 


.44 


.45 


.47 


.49 


.51 


.55 


3.6 


.36 


.38 


.40 


.41 


.43 


.45 


.47 


.49 


.50 


.52 


.54 


3.7 


.37 


.39 


.41 


.43 


.44 


.46 


.48 


.60 


.62 


.54 


.55 


3.8 


.38 


.40 


.42 


.44 


.46 


.47 


.49 


.61 


.63 


.65 


.57 


3.9 


.39 


.41 


.43 


.45 


.47 


.49 


.51 


.53 


.55 


.57 


.6S 


4.0 


.40 


.42 


.44 


.46 


.48 • 


.50 


.62 


.54 


.56 


.58 


.6C 


4.1 


.41 


.43 


.45 


.47 


.40 


.51 


.53 


.55 


.57 


.69 


.61 


4.2 


.42 


.44 


.46 


.48 


.50 


.52 


.55 


.57 


.69 


.61 


M 


4.3 


.43 


.45 


.47 


.49 


.52 


.54 


.66 


.58 


.60 


.62 


.64 


4.4 


.44 


.46 


.48 


.51 


.53 


.56 


.57 


.59 


.62 


.64 


.60 


4.5 


.45 


.47 


.49 


.52 


.54 


.66 


.58 


.61 


.63 


.65 


.67 


4.6 


.46 


.48 


.51 


.53 


.55 


.57 


.60 


.62 


.64 


.67 


.61 


4.7 


.47 


.49 


.52 


.54 


.56 


.69 


.61 


.63 


.66 


.68 


.7C 


4.8 


.48 


.50 


.53 


.55 


68 


.60 


.62 


.65 


.67 


.70 


.72 


4.9 


.49 


.51 


.54 


.56 


.69 


.61 


.64 


.66 


.69 


.71 


.78 


5.0 


.50 


.52 


.55 


.57 


.60 


.62 


.65 


.67 


.70 


.72 


.75 


5.1 


.51 


.54 


.56 


.59 


.61 


.64 


.66 


.69 


.71 


.74 


.76 


5.2 


.52 


.55 


.57 


.60 


.62 


.65 


.68 


.70 


.73 


.75 


.78 


5.3 


.58 


.56 


.58 


.61 


.64 


.66 


.69 


.72 


.74 


.77 


.7& 


5.4 


.54 


.57 


.59 


.62 


.65 


.67 


.70 


.73 


.76 


.78 


.81 


5.5 


.55 


.58 


.60 


.63 


.66 


.69 


.71 


.74 


.77 


.80 


.82 


5.6 


.56 


.59 


.62 


.64 


.67 


.70 


.73 


.76 


.78 


.81 


.84 


5.7 


.57 


.60 


.63 


.66 


.68 


.71 


.74 


.77 


.80 


.83 


.85 


5.8 


.58 


.61 


.64 


.67 


.70 


.72 


.75 


.78 


.81 


.84 


.87 


5.9 


.59 


.62 


.65 


.68 


.71 


.74 


.77 


.80 


.83 


.86 


.88 


6.0 


.60 


.63 


.66 


.69 


.72 


.75 


.78 


.81 


.84 


.87 


.90 



250 



Testing Milk and Its Products. 



Table X. Re\att\e-va\ue tables (Continued). 



1 


Price of milk per 100 pounds, In dollars and cents. 


3.0 


.46 


.48 


.49 


.51 


.52 


.54 


.55 


.57 


.58 


.60 


3.1 


.48 


.50 


.51 


.53 


.54 


.56 


.57 


.59 


.60 


.62 


3.2 


.50 


.51 


.53 


.54 


.56 


.58 


.59 


.61 


.62 


.64 


3.3 


.51 


.58 


.54 


.56 


.58 


.59 


.61 


.63 


.64 


.66 


3.4 


.53 


.54 


.56 


.58 


.59 


.61 


.63 


.65 


.66 


.68 


3.5 


.54 


.56 


.58 


.59 


.61 


.63 


.65 


.66 


.68 


.70 


3.6 


.56 


.58 


.59 


.61 


.63 


.65 


.67 


.68 


.70 


.72 


3.7 


.57 


.59 


.61 


.63 


.65 


.67 


.68 


.70 


.72 


.74 


3.8 


.59 


.61 


.63 


.65 


.66 


.68 


.70 


.72 


.74 


.76 


3.9 


.60 


.62 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


4.0 


.62 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


.80 


4.1 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


.80 


.82 


4.2 


.65 


.67 


.69 


.71 


.73 


.76 


.78 


.80 


.82 


.84 


4.3 


.67 


.69 


.71 


.73 


.75 


.77 


.80 


.82 


.84 


.86 


4.4 


.68 


.70 


.73 


.75 


.77 


.79 


.81 


.84 


.86 


.88 


4.5 


.70 


.72 


.74 


.76 


.79 


.81 


.83 


.85 


.88 


.90 


4.6 


.71 


.74 


.76 


.78 


.80 


.83 


.85 


.87 


.90 


.92 


4.7 


.73 


.75 


.78 


.80 


.82 


.85 


.87 


.89 


.92 


.94 


4.8 


.74 


.77 


.79 


.82 


.84 


.86 


.89 


.91 


.94 


.96 


4.9 


.76 


.78 


.81 


.83 


.86 


.88 


.91 


.93 


.96 


.98 


5.0 


.77 


.80 


.82 


.85 


.87 


.90 


.92 


.95 


.97 


1.00 


5.1 


.79 


.82 


.84 


.87 


.89 


.92 


.94 


.97 


.99 


1.02 


5.2 


.81 


.83 


.86 


.88 


.91 


.94 


.96 


.99 


1.01 


1.04 


5.3 


.83 


.85 


.87 


.90 


.93 


.95 


.98 


1.01 


1.03 


1.06 


5.4 


.84 


.86 


.89 


.92 


.94 


.97 


1.00 


1.03 


1.05 


1.08 


5.5 


.85 


.88 


.91 


.93 


.96 


.99 


1.02 


1.04 


1.07 


1.10 


5.6 


.87 


.90 


.92 


.95 


.98 


1.01 


1.04 


1.06 


1.09 


1.12 


5.7 


.88 


.91 


.94 


.97 


1.00 


1.03 


1.05 


1.08 


1.11 


1.14 


5.8 


.90 


.93 


.96 


.99 


1.01 


1:04 


1.07 


1.10 


1.13 


1.16 


5.9 


.91 


.94 


.97 


1.00 


1.03 


1.06 


1.09 


1.12 


1.15 


1.18 


6.0 


.93 


.96 


.99 


1.02 


1.05 


1.08 


1.11 


1.14 


1.17 


1.20 



Appendix. 



251 



Table X. Relative-value tables {Continued). 







Price of milk per 100 pounds, in dollars and cents. 


3.0 


.61 


.63 


.64 


.66 


.67 


.69 


.70 


.72 


.73 


.75 


3.1 


.64 


.65 


.67 


.68 


.70 


.71 


.73 


.74 


.76 


.78 


3.2 


.66 


.67 


.69 


.70 


.72 


.74 


.75 


.77 


.78 


.80 


3.3 


.68 


.69 


.71 


.73 


.74 


.76 


.78 


.79 


.81 


.83 


3.4 


.70 


.71 


.73 


.75 


.76 


.78 


.80 


.82 


.83 


.85 


3.5 


.72 


.73 


.75 


.77 


.79 


.80 


.82 


.84 


.86 


.88 


3.6 


.74 


.76 


.77 


.79 


.81 


.83 


.85 


.86 


.88 


.90 


3.7 


.76 


.78 


.80 


.81 


.83 


.85 


.87 


.89 


.91 


.93 


3.8 


.78 


.80 


.82 


.84 


.85 


.87 


.89 


.91 


.93 


.95 


3.9 


.80 


.82 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


4.0 


.82 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


1.00 


4.1 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


1.00 


1.03 


4.2 


.86 


.88 


.90 


.92 


.94 


.97- 


.99 


1.01 


1.03 


1.05 


4.3 


.88 


.90 


.92 


.95 


.97 


.99 


1.01 


1.03 


1.05 


1.08 


4.4 


.90 


.92 


.95 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


4.5 


.92 


.94 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


4.6 


.94 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


1.15 


4.7 


.96 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


1.15 


1.18 


4.8 


.98 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


1.15 


1.18 


1.20 


4.9 


1.00 


1.03 


1.05 


1.08 


1.10 


1.13 


1.15 


1.18 


1.20 


1.23 


5.0 


1.02 


1.05 


1.07 


1.10 


1.12 


1.15 


1.18 


1.20 


1.23 


1.25 


5.1 


1.05 


1.07 


1.10 


1.12 


1.15 


1.17 


1.20 


1.22 


1.25 


1.27 


5.2 


1.07 


1.09 


1.12 


1.14 


1.17 


1.20- 


1 22 


1.25 


1.27 


1.30 


5.3 


1.09 


1.11 


1.14 


1.17 


1.19 


1.22 


l!25 


1.27 


1.30 


1.32 


5.4 


1.11 


1.13 


1.16 


1.19 


1.21 


l!24 


1.27 


1.30 


1.32 


1.35 


5.5 


1.13 


1.15 


1.18 


1.21 


1.24 


1.26 


1.29 


1.32 


1.35 


1.38 


5.6 


1.15 


1.18 


1.20 


1.23 


1.26 


1.29 


1.32 


1.34 


1.37 


1.40 


5.7 


1.17 


1.20 


1.23 


1.25 


1.28 


1.31 


1.34 


1.37 


1.39 


1.43 


5.8 


1.19 


1.22 


1.25 


1.28 


1.30 


1.33 


1.3G 


1.39 


1.42 


1.45 


5.9 


1.21 


1.24 


1.27 


1.30 


1.33 


1.36 


1.39 


1.42 


1.45 


1.48 


6.0 


1.23 


1.26 


1.29 


1.32 


1.35 1.38 


1.41 


1.44 


1.47 


1.50 



252 



Testing Milk and Its Products. 







Table X. Relative-value tables 


{Continued). 






Il 




Price of milk per 100 pounds, in dollars and cents. 




3.0 


.76 


1 
.78 


.79 


.81 


.82 


.84 


.85 


.87 


.88 


.90 


3.1 


.79 


.81 


.82 


.84 


.85 


.87 


.88 


.90 


.91 


.93 


3.2 


.82 


.8-! 


.85 


.86 


.88 


.90 


.91 


.93 


.94 


.96 


3.3 


.84 


.86 


.87 


.89 


.91 


.92 


.94 


.96 


.97 


.99 


3.4 


.87 


.88 


.90 


.92 


.93 


.95 


.97 


.99 


1.00 


1.02 


3.5 


.89 


.91 


.93 


.94 


.96 


.98 


1.00 


1.01 


1.03 


1.05 


3.6 


.92 


.94 


.95 


.97 


.99 


1.00 


1.03 


1.04 


1.06 


1.08 


3.7 


.94 


.96 


.98 


1.00 


1.02 


1.03 


1.05 


1.07 


1.09 


1.11 


3.8 


.C7 


.99 


1.01 


1.03 


1.04 


1.06 


1.08 


1.10 


1.12 


1.14 


3.9 


.99 


1.01 


1.03 


1.05 


1.07 


1.09 


1.11 


1.13 


1.15 


1.17 


4.0 


1.02 


1.04 


1.03 


1.08 


1.10 


1.12 


1.14 


1.16 


1.18 


1.20 


4.1 


1.05 


1.07 


1.09 


1.11 


1.13 


1.15 


1.17 


1.19 


1.21 


1.23 


4.2 


1.07 


1.09 


1.11 


1.13 


1.15 


-1.18 


1.20 


1.22 


1.24 


1.26 


4.3 


1.10 


1.12 


1.14 


1.16 


1.18 


1.20 


1.23 


1.25 


1.27 


1.29 


4.4 


1.12 


1.14 


1.17 


1.19 


1.21 


1.23 


1.25 


1.28. 


1.30 


1.32 


4.5 


1.15 


1.17 


1.19 


1.21 


1.24 


1.26 


1.28 


1.30 


1.33 


1.35 


4.6 


1.17 


1.20 


1.22 


1.24 


1.26 


1.29 


1.31 


1.33 


1.36 


1.38 


4.7 


1.20 


1.22 


1.25 


1.27 


1.29 


1.32 


1.34 


1.36 


1.39 


1.41 


4.8 


1.22 


1.25 


1.27 


1.30 


1.32 


1.34 


1.37 


1.39 


1.42 


1.44 


4.9 


1.25 


1.27 


1.30 


1.32 


1.35 


1.37 


1.40 


1.42 


1.45 


1.47 


5.0 


1.27 


1.30 


1.32 


1.35 


1.37 


1.40 


1.42 


1.45 


1.47 


1.50 


5.1 


1.30 


1.33 


1.35 


1.38 


1.40 


1.43 


1.45 


1.48 


1.50 


1.53 


5.2 


1.33 


1.35 


1.37 


1.40 


1.43 


1.46 


1.48 


1.51 


1.53 


1.56 


5.3 


1.35 


1.38 


1.40 


1.43 


1.46 


1.48 


1.51 


1.54 


1.56 


1.59 


5.4 


1.38 


1.40' 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.59 


1.62 


5.5 


1.40 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.60 


1.62 


1.65 


5.6 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.60 


1.62 


1.65 


1.68 


5.7 


1.45 


1.48 


1.51 


1.54 


1.57 


1.60 


i.62 


1.65 


1.68 


1.71 


5.8 


1.48 


1.51 


1.54 


1.57 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


5.9 


1.50 


1.53 


1.56 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


1.77 


6.0 


1.53 


1.56 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


1.77 


1.80 



Appendix. 253 

Table XI. Butter chart, showing calculated yield of butter (in 
lbs.) from I to 10,000 lbs. of milk, testing 3.0 to 5.3 per 
cent. ' (See directions for use, p. 240. ) 



^ 

1 


3.00 


3.10 


3.20 


3.30 


3.40 


3.50 


3.60 


3.70 


3.80 


3.90 


4.00 


4.10 


t 


Milk, 
lbs. 


Milk, 
lbs. 


10,000 


325 


336 


348 


360 


371 


383 


394 


406 


418 


429 


441 


452 


10,000 


9,000 


293 


302 


313 


324 


334 


345 


355 


365 


376 


386 


397 


407 


9,000 


8,000 


260 


269 


278 


288 


297 


306 


315 


325 


334 


343 


353 


362 


8,000 


7,000 


228 


235 


244 


252 


260 


268 


276 


284 


293 


300 


309 


316 


7,000 


6,000 


195 


202 


209 


216 


223 


230 


236 


244 


251 


257 


265 


271 


6,000 


5,000 


163 


168 


174 


180 


186 


192 


197 


203 


209 


215 


221 


226 


5,000 


4,000 


130 


134 


139 


144 


148 


153 


158 


162 


167 


172 


176 


181 


4,000 


3,000 


97.5 


101 


104 


108 


111 


115 


118 


122 


125 


129 


132 


136 


3,000 


2,000 


65.0 


67.2 


69.6 


72.0 


74.2 


76.6 


78.8 


81.2 


83.6 


85.8 


88.2 


90.4 


2,000 


1,000 


32.5 


33.6 


34.8 


36.0 


37.1 


38.3 


39.4 


40.6 


41.8 


43.9 


44.1 


45.2 


l,00or 


900 


29.3 


30.2 


31.3 


32.4 


33.4 


34.5 


35.5 


36.5 


37.6 


38.6 


39.7 


40.7 


900 


800 


26.0 


26.9 


27.8 


28.8 


29.7 


30.6 


31.5 


32.5 


33.4 


34.3 


35.3 


36.2 


800 


700 


22.8 


23.5 


24.4 


25.2 


26.0 


26.8 


27.6 


28.4 


29.3 


30.0 


30.9 


31.6 


700 


600 


19.5 


20.2 


20.9 


21.6 


22.3 


23.0 


23.6 


24.4 


25.1 


25.7 


26.5 


27.1 


600 


500 


16.3 


16.8 


17.4 


18.0 


18.6 


19.2 


19.7 


20.3 


20.9 


21.5 


22.1 


22.6 


500 


400 


13.0 


13.4 


13.9 


14.4 


14.8 


15.3 


15.8 


16.2 


16.7 


17.2 


17.6 


18.1 


400 


300 


9.7 


10.1 


10.4 


10.8 


11.1 


11.5 


11.8 


12.2 


12.5 


12.9 


13.2 


13.6 


300 


200 


6.5 


6.7 


6.9 


7.2 


7.4 


7.6 


7.9 


8.1 


8.3 


8.6 


8.8 


9.0 


200 


100 


3.2 


3.4 


3.5 


3.6 


3.7 


3.8 


3.9 


4.1 


4.2 


4.3 


4.4 


4.5 


100 


90 


2.9 


3.0 


3.1 


3.2 


3.3 


3.4 


3.5 


3.6 


3.7 


3.8 


3.9 


4.1 


90 


80 


2.6 


2.7 


.2.8 


2.9 


3.0 


3.1 


3.2 


3.3 


3.4 


3.4 


3.5 


3.6 


80 


70 


2.3 


2.3 


2.4 


2.5 


2.6 


2.7 


2.8 


2.8 


2.9 


3.0 


3.1 


3.2 


70 


60 


1.9 


2.0 


2.1 


2.2 


2.2 


2.3 


2.4 


2.4 


2.5 


2.6 


2.7 


2.7 


60 


50 


1.6 


1.7 


1.7 


1.8 


1.9 


1.9 


2.0 


2.0 


2.1 


2.2 


2.2 


2.3 


50 


40 


1.3 


1.3 


1.4 


1.4 


1.5 


1.5 


1.6 


1.6 


1.7 


1.7 


1.8 


1.8 


40 


30 


1.0 


1.0 


1.0 


1.1 


1.1 


1.2 


1.2 


1.2 


1.3 


1.3 


1.3 


1.4 


30 


20 


.6 


.7 


.7 


.7 


.7 


.8 


.8 


.8 


.8 


.9 


.9 


.9 


20 


10 


.8 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.5 


10 


9 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


A 


.4 


.4 


.4 


.4 


9 


8 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


8 


7 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


6 


5 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


.1 


.1 


.1 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


3 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 
1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


2 

1 


Test. 


3.00 


3.10 


3.20 


3.30 


3.40 


3.50 


3.60 


3.70 


3.80 


3.90 


4.00 


4.10 


f 



254 



Testing Milk and Its Products. 









Table XI 


. Butter chart 


{Continued). 










4.20 


4.30 


4.40 


4.50 


4.60 


4.70 


4.80 


4.90 


5.00 


5.10 


5.20 


5.30 




JMilk 


























Milk 


lbs. 


























lbs. 


10,000 


464 


476 


487 


499 


510 


522 


534 


545 


557 


568 


580 


592 


10,000 


9,000 


418 


428 


438 


449 


459 


470 


481 


491 


501 


511 


522 


533 


9,000 


8,000 


371 


381 


390 


399 


408 


418 


427 


436 


446 


454 


464 


474 


8,000 


7,000 


325 


333 


341 


349 


357 


365 


374 


382 


390 


398 


406 


414 


7,000 


6,000 


278 


286 


292 


299 


306 


313 


320 


327 


334 


341 


348 


355 


6,000 


5,000 


232 


238 


244 


250 


255 


261 


267 


273 


279 


284 


290 


296 


5,000 


4,000 


186 


190 


195 


200 


204 


209 


214 


218 


223 


227 


232 


237 


4,000 


3,000 


139 


143 


146 


150 


153 


157 


160 


164 


167 


170 


174 


178 


3,000 


•2,000 


92.8 


95.2 


97.4 


99.8 


102 


104 


107 


109 


111 


114 


116 


118 


2,000 


1,000 


46.4 


47.6 


48.7 


49.9 


51.0 


52.2 


53.4 


54.5 


55.7 


56.8 


58.0 


59.2 


1,000 


900 


41.8 


42.8 


43.8 


44.9 


45.9 


47.0 


48.1 


49.1 


50.1 


51.1 


52.2 


53.3 


900 


800 


37.1 


38.1 


39.0 


39.9 


40.8 


41.8 


42.7 


43.6 


44.6 


45.4 


46.4 


47.4 


800 


700 


32.5 


33.3 


34.1 


34.9 


35.7 


36.5 


37.4 


38.2 


39.0 


39.8 


40.6 


41.4 


700 


600 


27.8 


28.6 


29.2 


29.9 


30.6 


31.3 


32.0 


32.7 


33.4 


34.1 


34.8 


35.5 


600 


500 


23.2 


23.8 


24.4 


25.0 


25.5 


26.1 


26.7 


27.3 


27.9 


28.4 


29.0 


29.6 


500 


400 


18.6 


19.0 


19.5 


20.0 


20.4 


20.9 


21.4 


21.8 


22.3 


22.7 


23.2 


23.7 


400 


300 


13.9 


14.3 


14.6 


15.0 


15.3 


15.7 


16.0 


16.4 


16.7 


17.0 


17.4 


17.8 


300 


200 


9.3 


9.5 


9.7 


10.0 


10.2 


10.4 


10.7 


10.9 


11.1 


11.4 


11.6 


11.8 


200 


100 


4.6 


4.8 


4.9 


5.0 


5.1 


5.2 


5.3 


5.5 


5.6 


5.7 


5.8 


5.9 


100 


90 


4.2 


4.3 


4.4 


4.5 


4.6 


4.7 


4.8 


4.9 


5.0 


5.1 


5.2 


5.3 


90 


80 


3.7 


3.8 


3.9 


4.0 


4.1 


4.2 


4.3 


4.4 


4.5 


4.5 


4.6 


4.7 


80 


70 


3.3 


3.3 


3.4 


3.5 


3.6 


3.7 


3.7 


3.8 


3.9 


4.0 


4.1 


4.1 


70 


60 


2.8 


2.9 


2.9 


3.0 


3.1 


3.1 


3.2 


3.3 


3.3 


3.4 


3.5 


3.6 


60 


50 


2.3 


2.4 


2.4 


2.5 


2.6 


2.6 


2.7 


2.7 


2.8 


2.8 


2.9 


3.0 


50 


40 


1.9 


1.9 


2.0 


2.0 


2.0 


2.1 


2.1 


2 2 


2.2 


2.3 


2.3 


2.4 


40 


30 


1.4 


1.4 


1.5 


1.5 


1.5 


1.6 


1.6 


1.6 


1.7 


1.7 


1.7 


1.8 


30 


20 


.9 


1.0 


1.0 


1.0 


1.0 


1.0 


1.1 


1.1 


1 1 


1.1 


1.2 


1.2 


20 


10 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


.6 


.6 


.6 


.6 


.6 


10 


9 


.4 


.4 


.4 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


.5 


9 


8 


.4 


.4 


^.4 


.4 


.4 


.4 


.4 


.4 


.5 


.5 


.5 


.5 


8 


7 


.3 


.3 


.3 


.4 


.4 


.4 


.4 


.4 


A 


.4 


.4 


.4 


7 


6 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


6 


5 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


5 


4 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


3 


.1 


.1 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


3 


2 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.] 


.1 


.1 


.1 


2 


1 


.1 

4.20 


.1 

4.30 


.1 
4.40 


.1 
4.50 


.1 
4.60 


.1 

4.70 


.1 

4.80 


.1 

4.90 


.1 

5. CO 


.1 
5.10 


.1 

5.20 


.1 

5.30 


1 


^ 
^ 


1 



Appendix. 



255 



Table XII. Overrun table, showing pounds of butter from 
one hundred lbs. of milk. (See directions for use, 

p. 18r.) 



Per 
























Per 


cent. 


1.10 


1.11 


1.12 


1.13 


1.14 


1.15 


1.16 


1.17 


1.18 


1.19 


1.20 


cent. 


fat. 


3.30 


3.33 


3.36 


3.39 


3.42 


3.45 


3.48 


3.51 


3.54 


3.57 


3.60 


fat. 


3.0 


3.0 


3.1 


3.41 


3.44 


3.47 


3.50 


3.53 


3.57 


3.60 


3.63 


3.66 


3.68 


3.72 


3.1 


3.2 


3.52 


3.55 


3.58 


3.62 


3.65 


3.68 


3.71 


3.74 


3.78 


3.81 


3.84 


3.2 


3.3 


3.63 


3.66 


3.70 


3.73 


3.76 


3.80 


3.83 


3.86 


3.89 


3.93 


3.96 


3.3 


3.4 


3.74 


3.77 


3.81 


3.84 


3.88 


3.91 


3.94 


3.98 


4.01 


4.05 


4.08 


3.4 


3.5 


3.85' 


3.89 


3.92 


3.96 


3.99 


4.03 


4.06 


4.10 


4.13 


4.17 


4.20 


3.5 


3.6 


3.96 


4.00 


4.03 


4.07 


4.10 


4.14 


4.18 


4.21 


4.25 


4.28 


4.32 


3.6 


3.7 


4.07 


4.11 


4.14 


4.18 


4.22 


4.26 


4.29 


4.33 


4.37 


4.40 


4.44 


3.7 


3.8 


4.18 


4.22 


4.26 


4.29 


4.33 


4.37 


4.41 


4.45 


4.48 


4.52 


4.56 


3.8 


3.9 


4.29 


4.33 


4.37 


4.41 


4.45 


4.49 


4.52 


4.56 


4.60 


4.64 


4.68 


3.9 


4.0 


4.40 


4.44 


i.48 


4.52 


4.56 


4.60 


4.64 


4.68 


4.72 


4.76 


4.80 


! 4.0 


4.1 


4.51 


4.55 


4.59 


4.63 


4.67 


4.72 


4.76 


4.80 


4.84 


4.88 


4.92 


4.1 


4.2 


4.62 


4.66 


4.70 


4.75 


4.79 


4.83 


4.87 


4-. 91 


4.96 


5.00 


5.04 


4.2 


4.3 


4.73 


4.77 


4.82 


4.86 


4.90 


4.95 


4.99 


5.03 


5.07 


5.12 


5.16 


4.3 


4.4 


4.84 


4.88 


4.93 


4.97 


5.02 


5.06 


5.10 


5.15 


5.19 


5.24 


5.28 


4.4 


4.5 


4.95 


5.00 


5.04 


5.09 


5.13 


5.18 


5.22 


5.27 


5.31 


5.36 


5.40 


4.5 


4.6 


5.06 


5.11 


5.15 


5.20 


5.24 


5.29 


5.34 


5.38 


5.43 


5.47 


5.52 


4.6 


4.7 


5.17 


5.22 


5.26 


5.31 


5.36 


5.41 


5.45 


5.49 


5.55 


5.59 


5.64 


4.7 


4.8 


5.28 


5.33 


5.38 


5.42 


5.47 


5.52 


5.57 


5.62 


5.66 


5.71 


5.76 


4.8 


4.9 


5.39 


5.44 


5.49 


5.54 


5.59 


5.64 


5.68 


5.73 


5.78 


5.83 


5.88 


4.9 


5.0 


5.50 


5.55 


5.60 


5.65 


5.70 


5.75 


5.80 


5.85 


5.90 


5.95 


6.00 


5.0 


5.1 


5.61 


5.66 


5.71 


5.76 


5.81 


5.87 


5.92 


5.97 


6.02 


6.07 


6.12 


5.1 


5.2 


5.72 


5.77 


5.82 


5.88 


5.93 


5.98 


6.03 


6.08 


6.14 


6.19 


6.24 


5.2 


5.8 


5.83 


5.88 


5.94 


5.99 


6.04 


6.10 


6.15 


6.20 


6.25 


6.31 


6.36 


5.3 


5.4 


5.94 


5.99 


6.05 


6.10 


6.16 


6.21 


6.26 


6.32 


6.37 


6.43 


6.48 


5.4 


5.5 


6.05 


6.11 


6.16 


6.22 


6.27 


6.33 


6.38 


6.44 


6.49 


6.55 


6.60 


5.5 


5.6 


6.16 


6.22 


6.27 


6.33 


6.38 


6.44 


6.50 


6.55 


6.61 


6.66 


6.72 


5.6 


5.7 


6.27 


6.33 


6.38 


6.44 


6.50 


6.56 


6.61 


6.67 


6.73 


6.78 


6.84 


5.7 


5.8 


6.38 


6.44 


6.50 


8.55 


6.61 


6.67 


6.73 


6.79 


6.84 


6.90 


6.96 


5.8 


5.9 


6.49 


6.55 


6.61 


6.67 


6.73 


6.79 


6.84 


6.90 


6.96 


7.02 


7.08 


5.9 


6.0 


6.60 


6.66 


6.72 


6.78 


/^.84 


6.90 


6.96 


7.02 


7.08 


7.14 


7.20 


6.0 



256 



Testing Milk and Its Froduds. 



Table XIII. Yield of cheese, correspond'ng to 2.5 to 6 per cent, 
of fat, with lactometer readings from 26 to 36. (See p. 188.) 



+i 






Lactometer degrees. 


4i 










gi4 


S3 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 


8=3 


2 J) 


7.28 


7.41 


7.54 


7.67 


7.8. 


7.94 


8.07 


8.20 


8.33 


8.47 


8.60 


2.5 


2!(1 


7.44 


7.' 7 


7.70 


7.83 


7.96 


8. ('9 


8.22 


8.35 


8.49 


8.02 


8.76 


2.6 


2.7 


7.5i» 


7.72 


7.85 


7.99 


8.1-' 


8.25 


8.38 


8.51 


8.64 


8.77 


8.91 


2.7 


2>. 


7.74 


7.87 


8.00 


8.14 


8.27 


8.40 


8.53 


8.67 


8.80 


8.91 


9.07 


2.R 


2.H 


7.90 


8.03 


8.16 


8.30 


8.44 


8.56 


8.69 


8.82 


8.95 


9.09 


9.22 


2.9 


3.0 


8.U0 


8.18 


8.31 


8.4". 


8.58 


8.71 


8.84 


8.97 


9.11 


9.24 


^.37 


3.0 


3.1 


8.21 


8.34 


8.47 


8.60 


8.74 


8.87 


9.00 


9.13 


9.26 


9.39 


9.53 


3.1 


3. -2 


8.36 


8. i^ 


h.62 


8.75 


8.89 


9.02 


9.15 


9.28 


9.42 


9.56 


9.68 


3.2 


3.0 


8.52 


8.65 


8.78 


8.91 


9.05 


9.18 


9.31 


9.44 


9.57 


9.70 


9.84 


3.3 


3.4 


8.67 


8.80 


8.93 


9.06 


9.20 


9.33 


9.46 


9.59 


9.73 


9.86 


9.99 


3.4 


3.^ 


8.82 


8.96 


9.09 


9.22 


9.35 


9. '8 


9.62 


9.75 


9.88 


10.01 


10.15 


3.5 


3.6 


8.98 


9.11 


9.2-i 


9.3. 


9.50 


9.63 


9.77 


9.90 


10.03 


10.17 


10.30 


3.6 


3.7 


9.13 


9.26 


9.39 


9.52 


9.65 


9.78 


9.92 


10.06 


10.19 


10.32 


10.46 


3.7 


3.- 


9.Z9 


9.42 


9.55 


9.68 


9.81 


9.94 


1(».0^ 


U'.21 


10.34 


10.48 


10.61 


3.8 


3.i) 


9.44 


9.57 


9.70 


9.84 


9.97 


10.10 


10.23 


10.36 


10.50 


10.64 


10.77 


3.9 


4.0 


9.60 


9.73 


9.86 


10.00 


10.13 


10.26 


10.39 


10.53 


10.66 


10.79 


10.93 


4.0 


4.1 


9.76 


9.88 


10.02 


.0.15 


10.28 


10.39 


10.54 


10.68 


10.81 


10.94 


11.08 


4.1 


4.2 


9.90 


lf^03 


10.17 


10.30 


10.43 


10.57 


10.70 


10.84 


10.97 


11.10 


11. 2^ 


4.2 


4.3 


10.06 


10.19 


10.32 


10.45 


10.58 


10.72 


10.85 


10.99 


11.12 


11.25 


11.39 


4.3 


4.4 


10.21 


10.34 


10.48 


10.61 


10.74 


10.87 


11.00 


11.14 


11.27 


11.41 


11.55 


4.4 


4.-5 


10.36 


10.49 


10.63 


10.76 


10.89 


11.03 


11.16 


11.29 


11.42 


11.56 


11.70 


4.5 


4.6 


10.52 


10.65 


10. 7^ 


10.92 


11.05 


11.18 


11.31 


11.45 


11.58 


.1.71 


11.85 


4.6 


4.7 


10.67 


10.81 


10.94 


11.07 


11.20 


11.34 


11.47 


11.60 


11.73 


11.87 


12. Oi 


4.7 


4.8 


10. SS 


10.96 


11.09 


11.22 


11.36 


11.49 


11.62 


11.76 


11.89 


12.02 


12.16 


4.8 


4.9 


10. 9h 


11.11 


11.25 


11.38 


11.51 


11.65 


11.78 


11.91 


12.04 


12.18 


12.32 


4.9 


5.( 


11.14 


11.27 


11.40 


11.54 


11.67 


11.80 


11.93 


12.07 


12.20 


12.34 


12.48 


5.0 


5.1 


'1.29 


11.42 


11.55 


11.69 


11.82 


11.96 


12.09 


12.23 


12.36 


12.49 


12.63 


5.1 


o.l 


11. 4o 


11.58 


11.71 


n.8o 


11.98 


12.11 


12.24 


12.38 


12.52 


12.66 


12.80 


5.2 


5.3 


11.60 


11.73 


11.86 


11.99 


12.13 


12.27 


12.40 


12.53 


12.67 


12.71 


12.85 


5.3 


0.4 


11.76 


11.89 


12.02 12.16 


12. 2h 


12.42 


12.55 


12.69 


12.83 


12.97 


13.01 


5.4 


5.5 


11.91 


12.04 


12.17 12.31 


12.44 


12.58 


12.71 


12.85 


12.99 


13.12 


13.25 


5.5 


3. J 


12.07 


12.20 


12.33 12.47 


12.60 


12.73 


12.87 


13.00 


13.14 


13.28 


13.41 


5.6 


5.^ 


12.22 


12.35 


12.48 12.62 


12.75 


12.89 


13.02 


13.16 


13.30 


13.44 


13.57 


"'.7 


5.8 


12.38 


12.51 


12.64 12.77 


12.91 


13.05 


13.18 


13.31 


13.45 


13.59 


13.72 


5.8 


5.ii 


12.53 


12.66 


12.79 12.93 


13.06 


13.19 


13.33 


13.47 


13.60 


13.74 


13.87 


5.9 


o.< 


I2.6U 


12.82 


12.95 13.09 


13.22 


13.35 


13.49 


13.62 


13.75 


13.89 


14.02 


6.0 



Appendix. 



257 



Table XIV. Comparisons of Fahrenheit and Centigrade 
(Celsius) thermometer scales. 



Fahren- 


Centi- 


Fahren- 


Centi- 


Fahren- 


Centi- 


heit. 


grade. 


heit. 


grade. 


heit. 


grade. 


+212 


+100 


+176 


+80 


+140 


+60 


211 


99-. 44 


175 


79.44 


139 


59.44 


210 


98.89 


174 


78.89 


138 


58.89 


209 


98.83 


173 


78.33 


137 


58.33 


208 


97.78 


172 


77.78 


136 


57.78 


207 


97.22 


171 


77.22 


135 


57.22 


206 


96.67 


170 


76.67 


134 


56.67 


205 


96.11 


169 


76.11 


133 


56.11 


204 


95.55 


168 


75.55 


132 


55.55 


203 


95 


167 


75 


131 


55 


202 


94.44 


166 


74.44 


130 


54.44 


201 


93.89 


165 


73.89 


129 


53.89 


200 


93.33 


164 


72.33 


128 


53.33 


199 


92.78 


163 


72.78 


127 


52.78 


198 


92.22 


162 


71.22 


126 


52.22 


197 


91.67 


161 


71.67 


125 


51.67 


196 


91.11 


160 


71.11 


124 


61.11 


195 


90.55 


159 


70.55 


123 


50.55 


194 


90 


158 


70 


122 


60 


193 


. 89.44 


157 


69.44 


121 


49.44 


192 


88.89 


156 


68.89 


120 


48.89 


191 


88.33 


155 


68.33 


119 


48.33 


190 


87.78 


154 


67.78 


118 


47.78 


189 


87.22 


153 


67.22 


117 


47.22 


188 


86.67 


152 


66.67 


116 


46.67 


187 


86.11 


151 


66.11 


115 


46.11 


186 


85.55 


150 


65.55 


114 


45.55 


185 


85 


149 


65 


113 


45 


184 


84.44 


148 


64.44 


112 


44.44 


183 


83.89 


147 


63.89 


111 


43.89 


182 


83.33 


146 


63.33 


110 


43.33 


181 


82.78 


145 


62.78 


109 


42.78 


180 


82.22 


144 


62.22 


108 


42.22 


179 


81.67 


143 


61.67 


107 


41.67 


178 


81.11 


142 


61.11 


106 


41.11 


177 


80.55 


141 


. 60.55 


105 


40.55 



111? 



258 



Testing Milk and Its Products. 



Table XIV. Comparisons of thermometer scales ( Continued. ) 



Fahren- 


Centi- 


Fahren- 


Centi- 


Fahren- 


Centi- 


heit. 


grade. 


heit. 


grade. 


heit. 


grade. 


+104 


+40 


+68 


+20 


+32 


+0 


103 


39.44 


67 


19.44 


31 


—0.55 


102 


38.89 


66 


18.89 


30 


i.n 


101 


38.33 


65 


18.33 


29 


1.67 


100 


37.78 


64 


17.78 


28 


2.22 


99 


37.22 


63 


17.22 


27 


2.78 


98 


36.67 


62 


16.67 


26 


3.33 


97 


36.11 


61 


16.11 


25 


3.89 


96 


35.55 


60 


15.55 


24 


4.44 


95 


35 


59 


15 


23 


5 


94 


34.44 


58 


14.44 


22 


5.55 


93 


33.89 


57 


13.89 


21 


6.11 


92 


33.33 


56 


13.33 


20 


6.67 


91 


32.78 


55 


12.78 


19 


7.22 


^ 90 


32 22 


54 


12.22 


18 


7.78 


89 


31.67 


53 


11.67 


17 


8.33 


88 


31.11 


52 


11.11 


16 


8.89 


87 


30.55 


51 


10.55 


15 


9.44 


86 


30 


50 


10 


14 


10 


85 


29.44 


49 


9.44 


13 


10.55 


84 


28.89 


48 


8.89 


12 


11.11 


83 


28.33 


47 


8.33 


11 


11.67 


82 


27.78 


46 


7.78 


10 


12.22 


81 


27.22 


45 


7.22 


9 


12.78 


80 


26.67 


44 


6.67 


8 


13.33 


79 


26.11 


43 


6.11 


7 


13.89 


78 


25.55 


42 


5.55 


6 


14.44 


77 


25 


41 


5 


5 


15.00 


76 


24.44 


40 


4.44 


4 


15.55 


75 


23.89 


39 


3.89 


3 


16.11 


74 


23.33 


38 


3.33 


2 


16.67 


73 


22.78 


37 


2.78 


1 


17.22 


72 


22.22 


36 


2.22 





17.78 


71 


21.67 


35 


1.67 


—1 


18.33 


70 


21.11 


34 


1.11 


2 


18.89 


69 


20.55 


33 


0.55 


3 


19.44 



To convert deg. Fahrenheit to corresponding deg. Centigrade: 
Subtract 32, multiply difference by 5, and divide by 9. 
Example: Which degree Centigrade corresponds to 110° F.? 110 - 32 = 

78; 78 X 5 = 390; 390 -*- 9 = 43.33. 

To convert deg. Centigrade to corresponding deg. Fahrenheit: 
Multiply by 9, divide product by 5, and add 32 to quotient. 
Example: Which degree Fahrenheit corresponds to 95.6° C? 95,5 X 9 = 

859.5; 859.5 -•- 5 = 171.9; 171.9 + 32 = 20R.fi. 



Appendix. 



259 



Table XV. Comparison of metric and customary weights and 

measures. 



Customary 

weights and 

measures. 



1 inch 

ifoot 

1 mile 

1 square inch.. 
1 square foot .. 
1 square yarJ. 

1 acre 

1 cubic inch... 
1 cubic foot. . . . 
1 cubic yard... 

1 bushel 

1 fluid ounce.. 

1 quart 

1 gallon 

1 grain 

1 ounce (av.).. 
1 pound (av. ) 



Equivalents in 
metric system. 



2.54 centimeters. 
.3048 meter. 
1.6094 kilometers. 
6.452 sq. centimeters. 
9.29 sq. decimeters. 
.836 sq. meter. 
.4047 hectare. 
16.387 cc. 
.0283 cub. meter. 
.765 cub. meter. 
.3552 hectoliter. 
29.57 cc. 
.9464 liter. 
3.7854 liters. 
64.8 milligrams. 
28.35 grams. 
.4536 kilogram. 



Metric weights 

and 

measures. 



1 meter 

1 meter 

1 kilometer.... 
1 sq. centimeter 
1 square meter. 
1 square meter. 

1 hectare 

Ice 

1 cub. decimeter 
1 cub. meter.. 
1 hectoliter... 

Ice 

inter 

1 decaliter 

1 gram 

1 gram 

1 kilogram.... 



Equivalents in 
customary system. 



,37 inches. 
.0936 yards. 
.6214 mile. 
.155 sq. inch. 
.764 sq. feet. 
.196 sq. yards. 
.471 acres. 
.061 cubic inch. 
.023 cubic inches. 
.314 cub. feet. 
.8377 bushels. 
.0338 fluid ounce. 
.0567 quarts. 
.6417 quarts. 
,43 grains. 
.035274 ounce. 
. 2046 pounds (av. 



2G0 Testing Milk and Its Products. 

SUGGESTIONS regarding the organization of co-operative 
creameries and cheese factories. 

When the farmers of a neighborhood are considering the 
establishment of a creamery or cheese factory, they should first 
of all make an accurate canvas of the locality to ascertain the 
number of cows that can*be depended on to supply the factory 
with milk. The area which may be drawn from will vary 
according to the kind of factory which it is desired to operate. 
A successful separator creamery will need at least 400 cows 
within a radius of four to five miles from the proposed factory.^ 
Small cheese factories can be operated with less milk, and 
gathered-cream and butter factories generally cover a much 
larger territory than that mentioned. In all cases, however, 
the question of the number of cows contributing to the enter- 
prise must be fully settled before further steps are taken, since 
this is a point upon which success will largely depend. 

Methods of organization. The farmers should form their own 
organization, and not accept articles of agreement proposed by 
traveling agents. An agreement to supply milk from a stated 
number of cows should be signed by all expecting to join the 
association. When a sufficient number of cows has been 
pledged to insure the successful operation of a factory, the farm- 
ers agreeing to supply milk should meet and form an organi- 
zation. This may be done according to either of the following 
plans which have been known to give good satisfaction. 

Raising money for building and equipment. 

Mrst. — Each member will sign an agreement to pay on or 
before a given date for a certain number of^hares in the com- 
pany at dollars per share; or, 

jS'econd. — An elected board of directors may be authorized to 

borrow a sum of money not exceeding thousand dollars 

on their individual responsibility, and the sum of cents, 

(usually five cents) per hundred pounds of milk received at 
the factory shall be reserved for the payment of this borrowed 
money. 

1 Bull. 56, Wisconsin experiment station. 



Appendix. ^61 

Constitution and by-laws of a co-operative association are drawn 
up and signed by the prospective members of the association 
when it has been determined to form such an association. It 
is impossible to include in an illustration all the articles and 
rules that may be found useful in each particular instance; the 
following suggestions in regard to some of the points to be in- 
cluded in the documents are given as a guide only. It may be 
found advisable to modify them in various ways to meet the 
needs of the organization to be formed. 

After the constitution and by-laws have been drawn up and 
made plain to all the members of the association, they should 
be printed and copies distributed to all parties interested. 

Constitution 

OR 

Articles of Agreement of the Association.^ 

1. The undersigned, residents within the Counties of , 

State of , hereby agree to become members of the 

Co-operative Association, which is formed for the purpose of 
manufacturing butter or cheese from whole milk. 

2. The regular meetings of the association shall be held an- 
nually' on the day of the month of Special 

meetings may be called by the president, or on written request 
of one-third of the members of the association, provided three 
day's notice of such meeting is sent to all members. 

Meetings of the board of directors may be called in the same 
way, either by the president or by any two members of the 
board of directors. 

3. Ten members of the association, or three of the board of 
directors, shall constitute a quorum for the transaction of busi- 
ness. 

4. The officers of the association shall include president, sec- 
retary, treasurer, one of whom is also elected manager, and 
these officers together with three other members of the associa- 



iThe following publications have been freely used in preparing this 
constitution and by-laws: Woll, Handbook f. Farmers and Dairymen; 
Minn, experiment station, bull. No. 35; Ontario Agriculture College, spec^ 
ial bulletin, May 1897. 



2G2 Teding Milk and Its Products. 

tion shall constitute the board of directors. Each of these six 
officers shall be elected at the annual meeting and hold office 
for one year, or until their successors have been elected and 
qualified. Any vacancies in the board of directors may be filled 
by the directors until the next annual meeting of the association. 

5. The duties of the president shall be to preside at all meet- 
ings of the association, and perform the usual duties of such 
presiding officers. He shall sign all drafts and documents of 
any kind relating to the business of the association, and pay 
all money which comes into his possession by virtue of his 
office, to the treasurer, taking his receipt therefor. He shall 
call special meetings of the association when deemed necessary. 

In the absence of the president, one of the board of directors 
shall temporarily fill the position. 

6. The secretary shall attend all business meetings of the 
association and of the board of directors and shall keep a care- 
ful record of the minutes of the meetings. He shall also give 
notices of all meetings and all appointments on committees, 
etc. He shall sign all papers issued, conduct the correspond- 
ence and general business of the association, and keep a correct 
financial account between the association and its members. He 
shall have charge of all property of the association not other- 
wise disposed of, give bonds for the faithful performance of his 
duties, and receive such compensation for his servi3es as the 
board of directors may determine. 

7. The treasurer shall receive and give receipt for all money 
belonging to the association, and pay out the same upon orders 
signed by the president and the secretary. He shall give such 
bonds as the board of directors may require. 

8. The board of directors shall audit the accounts of the 
association, invest its funds, appoint agents, and determine all 
compensations. They shall prescribe and enforce the rules and 
regulations of the factory. They shall cause to be kept a rec- 
ord of the weights and tests of the milk or cream received from 
each patron, the products sold, the running expenses, etc., and 
si all divide among the patrons the money due them each 
month. They shall also make some provision for the with- 



Appendix, 233 

drawal of any member from the association, and make a report 
in detail to the association at the annual meeting. Such report 
shall include the gross amount of milk handled during the 
year, the receipts from products sold, and all other receipts, the 
amounts paid for milk and for running expenses, and a com- 
plete statement of all other matters pertaining to the business 
of the association. 

9. Among the rules and regulations to be enforced by the 
board of directors may be included some or all of the following: 

a. Patrons shall furnish all the milk from all the cows prom- 
ised at organization of the association. 

b. Only sweet and pure milk will be accepted at the factory, 
and any tainted or sour milk shall be refused. 

c. The milk of each patron shall be tested at least three times 
a month. 

d. Any patron proved to be guilty of watering, skimming or 
otherwise adulterating the milk sent to the factory, or by tak- 
ing more than 80 pounds of skim milk or whey for every 100 
pounds of whole milk delivered to the factory, shall be fined as 
agreed by the association. 

e. A partron's premises may be inspected at any time by the 
board of directors, or their authorized agent, for the purpose of 
suggesting improvements in the methods of caring for the milk 
or the cows, in drainage and general cleanliness; or to secure 
samples of the milk of his cows for examination when it is 
deemed necessary. 

10. Any changes or amendments to the by-laws or constitu- 
tion of the association must be made in writing by the parties 
proposing the same, and posted prominently^ in a conspicuous 
place at the creamery, at least two weeks previous to their being 
acted upon. Such changes to be in force must be adopted by a 
two-thirds vote of the stockholders. 

11. In voting at any annual or special meeting of the asso- 
ciation, the members shall be entitled to one vote for each cow 
supplying milk to the factory, or for each share of the stock 
owned by them, as agreed upon. 



NDEX 



The figures refer to pages in the hook. 



Acid measures, 33, 46, 53. 

Acid tester, Swedish, 66. 

Acidity of cream, 118; estima- 
tion of, 123. . 

Acidity of milk, cause of, 108; 
determination of, 109, 213; 
methods of testing, 120. 

Accuracy of alkaline tablets, 
117. 

Adulteration of milk, 101, 106, 
224; calculation of, 106. 

Adulterated butter, 219; cheese, 
223. 

Albumen, 15; determination of, 
in milk, 209, 211. 

Albuminoids, 15. 

Albumose, 16. 

Alkaline tablet test, 113: stand- 
ard solution of, 116; accu- 
racy, 117. 

Alkaline tabs, 124. 

American Cheddar cheese, 22. 

Amphoteric reaction of milk, 
108. 

Analysis, chemical, of butter, 

216, 217; butter milk, 213; 

^cheese, 222; condensed milk, 

215; cream, 213; milk, 204; 

skim milk, 213; whey, 213. 

Appendix, 233. 

Artificial butter, detection of, 
219. 

Ash, determination of, in but- 
ter, 217, 218; in cheese, 223; in 
milk, 17, 212. 

Babcock test, the, 6, 28; Bart- 
lett's modification of, 71; 
direction for, 29; discussion of 
details, 37; for butter milk, 
89; for cheese, 89; for con- 
densed milk, 90; for cream, 
74, 169; for skim milk, 85; for 
whey, 89; glassware used in, 
-38; modifications of, 70; 
scales for weighing cream, 
cheese, etc., 82; water to be 
used in, 69. 



Bartlett's modification of Bab- 
cock test, 71. 

Bausch and Lomb centrifuge, 
72. 

Beimling test, 5. 

Bi-carbonate of soda, detection 
of, in milk, 229. 

Bi-chromate of potash, 98, 156; 
solution of, 99. 

Board of health degrees, 97, 236. 

Boiled milk, detection of, 227. 

Boiling test, the, 221. 

Boracic acid, in dairy products, 
124, 228. 

Borax in dairy products, 228. 

B.&W. bottle, 87. 

Butter, artificial, 13; detection 
of, 219. 

Butter chart, 253; use of, 185. 

Butter, 20; chemical analysis 
of, 216; complete analysis 
in same sample, 217; com- 
position of, 21, 233; defini- 
tion, 232; determination of 
ash, 217; casein, 216; fat, 216; 
water, 216; renovated, 222; 
sampling for analysis, 216; 
standard, 232; variations in 
composition, 177; yield, cal- 
culation of, 176. 

Butter fat, conversion factor 
for, 183; definition, 232; de- 
termination of specific grav- 
ity, 220; volatile fatty acids, 
220; expansion co-efiicient, 
36; price per pound, 190; 
specific gravity, 38; standard, 
231; table showing amounts 
due for, at 12 to 25 cents per 
pound, 247; test and yield of 
butter, 176. 

Butter making, quantities of 
products obtained in, 21. 

Butter milk, 21; Babcock test 
for, 89; chemical analysis of, 
213; composition of, 233; spe- 
cific gravity of, 214. 



Index. 



265 



Calculation of adulteration, 106; 
of concentration of condensed 
milk, 215; of milk solids, 99, 
100; of over-run, 183; of sp. 
gr. of milk solids, 103; of 
yield of butter, 176, 182, 184; 
of cheese, 187; of dividends 
at creameries, 190; at cheese 
factories, lyt>; of percentages, 
159. 

Calibration of glassware, 47. 

Carbohydrates, 16. 

Casein, 14; determination of, in 
butter, 216; in cheese, 223; in 
milk, 209, 211. 

Centrifugal machines, 54. 

Chamberland filters, 15. 

Cheddar cheese, American, 22; 
composition, 233. 

Cheese, 22; Eabcock test for, 
89; calculating yield of, from 
casein and fat, 189; from fat, 
187; from solids not fat and 
fat, 188; composition, 233; 
chemical analysis of, 222; 
definitions, 282; determina- 
tion of ash, 2z,d; casein, 223; 
fat, 222; water, 222; "filled," 
detection of, 223; quality of, 
from milk of different rich- 
ness, 200; sampling, 89; 
standard, 232; yield, calcula- 
tion of, 187; yield of, and 
quality of milk, relation be- 
tween, 188. 

Cheese factories, calculating 
dividends at, 199; co-opera- 
tive, 202; proprietary, 202. 

Cholesterin in milk, 19. 

Citric acid in milk, 19. 

Cleaning solutions for test bot- 
tles, 44. 

Cleaning test bottles, 40; ap- 
paratus for, 41. 

Cochran's test, 5. 

Coloring matter in milk, for- 
eign, -detection of, 226. 

Colostrum milk, 19; composi- 
tion of, 233. 

18 



Composite samples, 148.; care 
of, 158; case for holding, 154; 
methods of taking, 148; pre- 
servatives for, 155. 

Composite sampling, accuracy 
of, 155; use of drip sample, 
150; one-third sample pip- 
ette, 153; Scovell sampling 
tube, 151; tin dipper, 148; 
equity milk sampler, 153. 

Composition of butter, 233; but- 
ter milk, 233; cheese, i233; 
colostrum milk, 233; con- 
densed milk, 233; cream, 233; 
milk, 19, 233; milk ash, 18; 
skim milk, 233; whey, 233. 

Condensed milk, 22; analysis 
of, 215; composition of, 233; 
determination of concentra- 
tion, 216; of sp. gr. of, 215; 
testing of, 90, 91. 

Control sample of milk, 101. 

Conversion factor for butter 
fat, 183. 

Conversion tables for thermo- 
meter scales, 257; for weights 
and measures, 258. 

Cows, number of tests required 
in testing, 136; when to test, 
138. 

Cows' milk, composition of, 19, 
233. 

Cream, 20; acidity of, 120; Bab- 
cock test for, 73, 169; bottles, 
the bulb-necked, 76; the Win- 
ton, 77; care in sampling, ne- 
necessity of 171; definition, 
232; determinauon of "acidity 
of, 114, 123; errors of mea- 
suring in testing. 74; evap(y 
rated, 232; gelatin in, detec- 
tion of, 227; pasteurized, de- 
tection of, 226- scales, 78; 
separator, 20; separation of, 
infiuence of temperature, 174; 
spaces, 165; specific gravity, 
75; standard, 232; starch in, 
228; testing, 73; testing outfit, 
170; testing at creameries, 
165; use of 5 cc, pipette in, 



266 



Testing Milk and Its Products. 



82; use of milk test bottles 
in, 81; test bottles, 76 ; weight 
of, delivered by a 17.6 cc. 
pipette, 75. 

Creameries, calculating divi- 
dends at, 190, 192; co-opera- 
tive, 191; cream testing at, 
165; proprietary, 191. 

Creamery inch, 1, 167. 

Curd test, the Wisconsin im- 
proved, 125. 

Definitions of milk and its 
products, 231. 

DeLaval's butyrometer, 8. 

Devarda's acidimeter, 113. 

Diameter of tester and speed 
required, relation between, 57. 

Dividends, calculating, at cheese 
factories, 199; at creameries, 
190; of both milk and cream 
at the same factory, 198. 

Dividers, Lutley, 37. 

Double-necked test bottles, 87; 
value of divisions of, 87. 

Draining rack for test bot- 
tles, 43. 

Equity milk sampler, 153. 
Expansion coefRcient for butter 
fat, 36. 

Failyer and Willard's test, 5. 

Farrington's alkaline tablet 
test, 113. 

Fat, 12; color of, an index to 
strengtn of acid used, 66; 
content, causes of variation 
in, 135; determination of, in 
butter, 216; in cheese, 222; 
in milk, 208; globules, 12; in- 
fluence of temperature on 
separation of, 67; measuring 
of, in cream testing, 83; in 
milk testing, 35; pounds in 
1-10,000 lbs. of milk, testing 3 
to 5.35 per cent., 241; speed 
required for complete sepa- 
ration of, 56. 

Fermentation test, the, 128. 

Filled cheese, detection of, 223. 



"Fitch's Salt Analysis," 218. 
Fjord's centrifugal cream test, 

9. 
Fluorids, detection of, in nilk, 

230. 
Food, influence of, on quality 

of milk, 143, 145. 
Food standards. Government, 

231. 
Fool pipettes, 45. 
Formaldehyd, detection of, in 

milk, 230. 
Frozen milk, sampling of, 27. 

Gauges of cream, 165. 

Gelatine in cream, detection of, 

227. 
Gerber's acid-butyrometer, 7; 

fermentation test, 128. 
Glassware used in the Babcock 

test, 38; calibration of, 47. 
Globulin, 15. 

Glycerides of fatty acids, 13. 
Goat cheese, 14. 
Government food standards, 

231. 
Grain-feeding, heavy, influence 

of, on quality of milk, 143. 
Gurler's method of testing 

cows, 138. 

Hand testers, 59. 

Hemi-albumose, 15. 

Herd milk, variations in, 142; 

ranges in variation of, 143. 
±iypoxanthin 19. 

Introduction, 1. 
Iowa station test, 5. 

Kumiss, 231. 

Lactic acid in milk, 16. 

Laetocrite, 5, S. 

Lactose, 16. 

Lactochrome, 19. 

Lactometer, the, and its appli- 
cation, 93; bi-chromate, in- 
fluence on, 98; cleaning of, 99; 
degrees, 94; N. T. board of 
health, 96, 236; Quevenne, 93; 
reading the, 97; time of tak- 
ing readings, 98. 



Index. 



267 



Lecithin in milk, 19. 
Leffmann and Beam test, 5. 
Leg-al standards for milk, 102, 

235. 
Liebermann's method, 5. 
Lutley dividers, 37. 

Manns' test, 110. 

Marschall rennet test, 130. 

Measuring fat column in test- 
ing cream, 83; in testing milk, 
35. 

Mercury, calibration with, 47; 
cleaning, 48. 

Metric and customary systems 
of weights and measures, 
comparison of, 259. 

Milk, acidity of, 108; adultera- 
tion of, 101; amphoteric re- 
action of, 108; ash, composi- 
tion of, 19; boiled, detection 
of, 227; chemical analysis of, 
204; cholesterin in, 19; citric 
acid in, 19; . colostrum, 19; 
composition of, 11; table 
showing composition of, 233; 
composite sampling of, 148; 
condensed, 22, 90, 233; correc- 
tion taoie for specific grav- 
ity, 237; definitions, 231; de- 
tection of preservatives in, 
124, 22«; determination of 
acidity, 120, 213; of ash, 212; 
of casein and albumen. 209, 
211; of fat, 208; of milk sugar, 
212; of specific gravity, 204; 
of water, 207, 208; fat avail- 
able for butter in different 
grades of, iS2; from cows in 
heat, 102; from sick cows, 
102; from single cows, sam- 
pling of, 139; variations in, 
131; frozen, sampling of, 27; 
gases, 19; hypoxanthin, 19; 
lactochrome, 19; lecithni, 19; 
legal standards, 102, 234; mi- 
croscopic impurities, 228; 
mineral components, 18; par- 
tially churned, sampling of, 
24; quality of, influence of 
food, 145; of heavy grain 



feeding, 143; of pasture, 145; 
method of improving, 146; 
sampling, 26; scales, 139; 
serum, 11; skimming, 156; 
solids, 11; calculation of, 99; 
specific gravity of, 103; sour- 
ing of, 16; sour, sampling of, 
25; standards, 102, 231, 234; 
sugar, 16; testing purity of, 
125; urea, 19; water, 12; 
watering of, 106; watering 
and skimming, ,106. 

Milk test, a practical, need of, 
1; requirements of, 6; bottle, 
use of, in testing cream, 81; 
Russian, 70. 

Milk tests, Beimling (Leff- 
mann and Beam) 5; 'Cochran, 
5; DeLaval butyrometer, 8; 
Failyer and Willard, 5; Fjord, 
9; foreign, 7; Gerber acid- 
butyrometer, 7; introduction 
of, 4; lactocrite, 5, 8; Lieber- 
mann, 5; Nahm, 5; Parson, 5; 
Patrick (Iowa station test), 
5; reiractometer, 10; Rose- 
Gottlieb, 5; Schmied, 5; Short, 
4; Thorner, 5. 

Milk products, composition of, 
19, 233. 

Monrad rennet test, the, 129. 

Milk testing, 29; on the farm, 
131. 

N. Y. board of health lacto- 
meter, 96; degrees correspond- 
ing to Quevenne lactometer 
degrees, 236. 

Nafis modification of test bot- 
tle calibrator, 52. 

Nitric acid test for adulteration 
of milk, 224. 

Non-fatty milk solids, 11. 

Normal solutions, 110. 

Nuclein, 15. 

Oil-test churn, 2, 166. 
Ohlsson test bottle, 87.. 
Oleomargarine, detection of, 
219; cheese, detection of, 223. 



268 



Testing Milk and Its Products. 



One-third sampling pipette, use 
of, 153. 

Organization of co-operative 
creameries and cheese fac- 
tories, suggestions concern- 
ing, 260. 

Overrun, 179; calculation of. 
183; factors influencing, 179; 
table, 186, 255. 

Parson's test, 5. 

Pasteurized milk or cream, de- 
tection of, 226. 

Pasture, influence of, on quality 
of milk, 145. 

Patrick's test, 5. 

Patron's dilemma, a, 162. 

Percentages, average, methods 
of calculation, 160; fallacy of 
averaging, 159. 

Phenolphtalein, 111. 

Physician's centrifuge, use of, 
in milk testing, 73. 

Pipettes, 44, 53; proper con- 
struction of points, 45; pro- 
per method of emptying, 31; 
calibration, 53. 

Potassium bi-chromate, 156. 

Power testers, 61. 

Preservaline, 124, 220; detec- 
tion of, in milk, 124, 

Preservatives, for composite 
samples, 156; in milk, detec- 
tion of, 124, 220. 

Primost, 14. 

Process butter, detection of, 
222. 

Proteose, 15. 

Quevenne lactometer, the, 93; 
degrees corresponding to 
scale of N. Y. board of health 
lactometer, 96, 236. 

Recknagel's phenomenon, 98. 
Refractometer, 10. 
Reichert number, 221. 
Reichert-Wollny method, 220. 
Relative-value tables, 196, 249. 
Rennet tests, 129. 



Renovated butter tests, for de- 
tection of, 221; boiling test, 
221; Waterhouse test, 221. 

Reservoir for water in Babcock 
test, 71. 

Rose-Gottlieb method, 5. 

Russian milk test, the. 70.. 

Salicylic acid, in milk, detec- 
tion of, 230. 

Salt, estimation in butter, 218. 

Sampling cheese, 89; milk, 23, 
29; milk from single cows, 
139. 

Sampling tube, for cream, 171; 
Scovell, 151; equity, 153. 

Scales for weighing cream, 78; 
milk, 139. 

Schmied method, the, 5. 

Scovell sampling tube, 151. 

Serum solids, 11. 

Short's test, 4. 

Siegfeld's modification of Bab- 
cock's test, 73. 

Sinking fund, 195. 

Separator cream, 20. 

Skimming of milk, detection of, 
106. 

Skim milk, 20; Babcock test 
for, 85; chemical analysis of, 
213; composition of, 233; test 
bottles, 87, 88. 

Solids not fat, 11; formulas for 
calculating, 100; tables show- 
ing, corresponding to 0-6 per 
cent, fat and 26-36 lactometer 
degrees, 238. 

Sour milk, sampling of, 26. 

Space system, the, 165. 

Specific gravity, 93: cylinders, 
94, 97; influence of tempera- 
ture, 95; of butter fat, deter- 
mination of, 220; of butter 
milk, 214; of condensed milk, 
215; of milk, 204, 206; of milk 
solids, 103; of sour milk, 214; 
temperature correction table, 
237. 

Speed required for complete 
separation of fat, 55. 



Index. 



269 



Spillman's cylinder, 120. 

Standard measure for calibrat- 
ing test bottles, 52. 

Standards of purity, Govern- 
ment, for milk and its prod- 
ucts, 231. 

Starch in cream, 228. 

Steam turbine testers, 61, 62. 

Sulfuric acid, 63; table showing 
strength of, 65; testing 
strength of, 64. 

Sweetened condensed milk, 91. 

Swedish acid bottle, 46. 

Swedish acid tester, 66. 

Tank for cleaning test bottles, 
43. 

Temperature of turbine testers, 
62; of fat when tests are read, 
36. 

Test bottles, 31, 38; apparatus 
for cleaning, 42: bulb-necked 
cream, 78; calibration, 53; 
cleaning, 40; cream, 78; 

> double -necked, 87; draining- 
rack for, 41; marking, 39; for 
cream testing, 78; for skim 
milk testing. 87; rack for use 
in creameries and cheese fac- 
tories, 154; tank for cleaning, 
43, Winton cream, 79. 

Testers, 54; ascertaining speed 
of, 58; hand, 59; power, 61. 

Testing cows, number of tests 
required during a period of 
lactation, 136. 

Testing milk and its products, 
1; on the farm, 131. 

Test sample, size of, 142. 

Thermometer scales, compari- 
son of, 257. 

Thermometer in frame of tur- 
bine testers, 63. 

Thcirner's method, 5. 

Total solids in milk, 11; deter- 
mination of, 208. 

Trowbridge method of calibra- 
tion, 50. 

Turbine testers, 61, 62. 

Variation in composition of 
butter, 177. 



Variation in quality of milk, 
131, 143; causes of, 135; lati- 
tude of, 102; ranges in, 143. 

Volatile acids, 220. 

Wagner skim milk bottle, 88. 

Waste acid jar, 41. 

Water, calibration with, 49; de- 
termination of, in butter, 216; 
in cheese, 2^6; in milk, 207, 
208; oil-stove for heating, 34; 
reservoir for, 69; to be used 
in tne Babcock test, 68. 

Waterhouse test, 221. 

Watering of milk, detection of, 
106. 

Watering and skimming of 
milk, detection of, 106. 

Weights and measures, compar- 
ison of metric and customary, 
257. 

Westphal balance, 206. 

Whey, 22; Babcock test for, 89; 
chemical analysis of, 213; 
composition of, 233; defini- 
tion, 232. 

Winton cream bottle, the, 79. 

Wisconsin creamery butter, 
summary of analyses, 178. 

Wisconsin curd test, the im- 
proved, 125. 

Wollny's refractometer, 10. 

World's Fair breed tests, com- 
position of butter from, 177; 
variation in quality of milk, 
142. 

Yield of butter, calculation of, 
176; and butter fat test, 176; 
irom milk of different rich- 
ness, 182; table showing, 
from 1 to 10,000 lbs. of milk, 
testing 3 to 5.35 per cent., 253. 

Yield of cheese, calculation of, 
187; relation between, and 
quality of milk, 187; table 
showing, corresponding to 
2.5 to 6 per cent, of fat, with 
lactometer readings of 26 to 
36, 256. 



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§ 



The De Laval Separator Co. 

Randolph & Canal Sts. 1 2 1 Youville Square, 

O CHICAGO. General Offices: Montreal. « 

O 1213 Filbert Street, -, . a>^„^. »».,^^ o-.- 75 & 77 York Street, 

O PHILADELPHIA. 74 CORTLANDT ST,. ^-oroNTO. 

O 9 & M Drumm St., new YORK. 248 McDermot Ave., 

O SAN FRANCISCO WINNIPEG. 




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Accurate Creamery Glassware 

I like to make glassware for the man who 

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quality, prompt services and low prices. 

Anyone can make it for the man that does 
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Each and every piece of graduated glass- 
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and when in need of a new supply and you 
want such goods as I furnish to Dairy 
Commissioners and Dairy Schools in the 
United States and Canada, send me your 
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Illustrated and Descriptive Catatogue Free upon Request 

LOUIS F. NAFIS 

EXPERT SPECIALIST, MILK TESTING APPARATUS 
120-122 Randolph St. CHICAGO 




Chr. Hansen's Lactic Ferment 

improves the flavor, uniformity and 
keeping quality of butter and cheese 

THE MARSCHALL RENNET TEST 

is indispensible for testing the milk 
in the Cheese Vat 



We are the manufacturers of Chr. Hansen's 
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Tablets and Cheese Color Tablets, Danish 
Butter Color and Columbian Butter Color. 



Write us for Descrip- 
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Chr. Hansen's a 

Laboratory \ 

Box 1031 A 

LIHLE FALLS, N. Y. i 




TWO LEADERS 

The Urn Sm Segtapsttor and 
Agos Babcock Testerm 

The U. S. Separa- 
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As to the Superiority of the Agos Tester, we need but to 
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Wisconsin Agrl. Exp. Station, Madison, Wis. 
The Turbine and Hand Agos Milk Testers, which 
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Tester. E. H. Farrington, (Prof. Dairy Husbd'y. } 




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Address all Letters to 

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BELLOWS FALLS, VERMONT 



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K WE MANUFACTURE EVERY K 

§ Apparatus and Instrument | 

8 PERTAINING TO THE TESTING S 

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Warner's Patent Double-bore Skimmilk Test Bottle 
Wagnep's Patent Perfection Milk Test Bottle 
Ohisson's Patent Double-neck Skimmilk Test Bottle 
Russian Patent Pipette 
Russian Patent Test Bottle and Reading Tubes 

Our glassware is handled by every reliable Dairy Supply 
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Our prices are right and our instruments are manufactured 
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Illustrated Price List Mailed upon Application 

THE WAGNER GLASS WORKS 

965-967 East 132d St., New York, N. Y. 




I ElMIL GREIINEIR § 

O NENA/ VORK CITV 

O First Manufacturer o£ Babcock Test-bottles 

O 

§ Guaranteed accurate goods for the Testing of ^ 
§ MILK, CREAM, BUTTER, CHEESE, ETC. | 

Farrin^ton's Alkaline Tablets 

For testing the acidity 
of milk and cream 

Bi-Chromate Tablets 
Blue Pill Tablets . . . 

For preserving composite 
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Wisconsin Visco^en 

For restoring the thickness' 
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MANUFACTURED BY 

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Station R, Chica^o, 111. 



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BOOKS 



The following books on dairying and related topics 
will be sent, postage prepaid, upon re- 
ceipt of the price ^iven. 



Woll, Handbook for Farmers and Dairymen. Third ed., 

New York, 1903, 438 pp «1 50 

Qrotenfelt-Woll, Principles of Modern Dairy Practice. 

Third ed.. New York, 1899, 286 pp $2 00 

Wing, Milk and its Products. Sixth ed., New York, 1903, 

311 pp $1 00 

Fleischmann, The Book of the Dairy. London and New 

York, 189B,344pp $4 00 

Richmond, Dairy Chemistry. London and Philadelphia, 

1900, 384 pp $4 50 

Snyder, Chemistry of Dairying. Easton, Pa., 1897, 157 pp... $1 50 

pecker, Cheese Making. Columbus, O., 1900, 192 pp $1 75 

Decker, Elements of Dairying. Columbus, O., 1903, 116 pp.. $1 00 

Dean, Canadian Dairying. Toronto, 1903, 260 pp $1 00 

The Creamery Patron's Handbook. Chicago, 1903, 309 pp... U 00 
Russell, Dairy Bacteriology. Fifth ed., Madison, Wis., 1903, 

214 pp 81 00 

Gurler, American Dairying. Chicago, 1894, 267 pp fl 00 

Belcher, Clean Milk. New York, 1903, 146 pp fl 00 

Monrad, A B C in Buttermaking. Winnetka, 111, 1900, 68 pp. 50 
Monrad, A B C in Cheesemaking. Winnetka, 111., 1900, 68 pp. 50 
Vye, Creamery Accounting. St. Anthony Park, Minn., 1900. fl 00 
Bailey, Principles of Agriculture. New York, 1901, 300 pp.. $i 25 
Storer, Agriculture. Seventh ed.. New York, 1897, 3 vols... $5 00 
Henry, Feeds and Feeding. Fourth ed., Madison, Wis., 

i902, 657 pp 12 00 

Jordan, The Feeding of Animals. New York, 1901, 450 pp.. $1 25 
Woll, A Book on Silage. Revised ed., Chicago, i901, 234 pp. $1 00 
Peer, Soiling, Ensilage, and Stable Construction. New 

York, 1900, 247 pp $1 00 

Shaw, The Study of Breeds. New York, 1901, 371 pp $1 50 

Craig, Judging Live Stock. Second ed., Des Moines, la., 

1901, 193 pp «2 00 

King, The Soil. Eighth ed., New York, 1903, 303 pp U 00 

King, The Physics of Agriculture. Second ed., Madison, 

Wis., 1901, 604 pp U 76 

Hopkins, Veterinary Elements. Second ed., 1901, 286 pp.... $1 50 
QoS, Principles of Plant Culture. Second ed., Madison, 

Wis., 1899,276 pp SI 25 

Adams, The Modern Farmer. San Francisco, Cal., 1899, 

662 pp $2 00 



Meindoxa Book Co., 

MADISON, WIS. 



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MAY 2 1904 






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